About this page

This consolidated page combines the full West Gate Bridge statistical output with the additional early tunnel-impact findings, truck-share analysis and first corridor-level sensor work.

Generated at: 2026-03-19 14:17:55

The database contains 132,389,534 rows across 6 tables, with raw TIRTL coverage from 2025-11-01 to 2026-03-15. The raw network spans 302 distinct sites.

The bridge-focused table contains 25,767 fifteen-minute bridge observations. Average bridge load is 3,750.7 vehicles/hour, with a maximum observed bridge flow of 10,484 vehicles/hour. Average observed speed is 67.9 km/h, but the minimum drops to 13.8 km/h, indicating clear stress periods.

Early comparison work also suggests weekday bridge traffic fell from 192,875.2 to 178,502.2 vehicles/day after the opening split, the weekday inbound 7am–9am peak eased, and the first validated South Wharf / ramp-adjacent sensors showed modest overall reductions with stronger softening at selected peak hours.

Top-line reading:
The strongest evidence currently available points to partial easing and redistribution rather than a dramatic collapse in demand: the bridge remains heavily used, but the weekday inbound peak and some nearby corridor pressure appear to have softened in the early operating period.

This page is a single consolidated public reference for the website. All figures are computed directly from raw TIRTL data without manual adjustment, then assembled into one page for easier review when media coverage goes live.

5 Key Takeaways

The West Gate Bridge remains one of Melbourne’s heaviest-used road corridors even after the early tunnel-opening changes.
Average weekday bridge traffic is lower in the current comparison window, but demand has clearly shifted rather than vanished.
The clearest early improvement appears in the weekday inbound morning peak, where speeds improved and flow softened.
Truck share and selected nearby corridor sensors also point to partial redistribution of pressure across the wider network.
The current evidence supports a story of easing and rebalancing, not a dramatic emptying of the bridge.

Why This Matters to Melbourne Drivers

For ordinary drivers, this analysis matters because it moves the conversation beyond vague claims and into measured reality. It helps answer practical questions people care about: whether the bridge is genuinely less crowded, whether morning trips are improving, whether trucks have shifted, and whether congestion has eased on nearby approaches rather than simply moving from one choke point to another.

In simple terms, the current data suggests the West Gate Tunnel has already had some real effect, especially at selected peak periods, but the West Gate Bridge is still under heavy structural demand. That means Melbourne drivers may benefit from some relief, but should not expect the corridor to suddenly behave like a lightly used road. The bridge still matters enormously, and ongoing data monitoring is essential to show whether early improvements strengthen, plateau, or fade over time.

Executive Summary

Key findings from current analysis:

Average weekday bridge traffic reduced by 14,373 vehicles/day following the tunnel opening comparison split.
Morning inbound peak speeds improved from 46.4 km/h to 55.1 km/h.
Inbound truck share declined from 21.33% to 18.80%.
Key corridor sensors recorded reductions of approximately 5–7%.
Peak congestion periods softened, but bridge demand remains structurally strong.

Overall, the available data points to redistribution rather than collapse of demand. The West Gate Bridge remains one of Melbourne's most heavily used transport corridors, even after the early tunnel-opening changes visible in this dataset.

Data Currency

Dataset coverage: 2025-11-01 to 2026-03-15
Latest raw data date: 2026-03-15
Page last generated: 2026-03-19 14:17:55

This page can be regenerated as additional sensor data becomes available.

What These Results Suggest

Interpreting the statistical findings in practical corridor terms.

Traffic demand has shifted, not disappeared.
The tunnel appears to have introduced measurable redistribution across the wider corridor.
The weekday morning inbound peak shows the clearest early relief.
Bridge utilisation remains structurally high despite the observed reductions.
Congestion behaviour still reflects broader feeder-road pressure, not just one isolated bottleneck.

These early results suggest that major infrastructure changes may soften peak behaviour before producing very large absolute reductions in total daily traffic.

Data Confidence and Limitations

The analysis period currently spans November 2025 to March 2026.
The tunnel comparison reflects an early operating window, not a mature long-run equilibrium.
Some corridor locations remain without full sensor coverage.
Seasonal conditions and summer travel patterns may influence part of the early signal.
Stronger long-term conclusions will require continued monitoring over additional quarters.

All calculations are derived directly from raw TIRTL data using automated processing methods. No manual smoothing or hand adjustment has been applied to the headline metrics shown on this page.

System Architecture Overview

High-level outline of how the statistical outputs on this page were produced.

Raw TIRTL data ingestion pipeline.
Structured database architecture for bridge and corridor analysis.
Baseline modelling using time-of-day and day-of-week comparison logic.
Automated aggregation into daily, hourly and peak-window summaries.
Script-driven chart generation and public-page assembly.
Repeatable regeneration workflow as new data becomes available.

The workflow is designed to support transparent, repeatable updates rather than one-off manual analysis.

Jump to section

5 Key Takeaways
Why This Matters to Melbourne Drivers
Executive Summary
Data Currency
What These Results Suggest
Data Confidence and Limitations
System Architecture Overview
Headline Metrics
Early Tunnel Impact
Peak-Window and Truck Follow-Up
Corridor / South Wharf Analysis
Visual Analysis
Database Overview
Bridge Summary
Direction Split
Peak Bridge Intervals
Slowest Bridge Intervals
Slowest High-Volume Intervals
Top Baseline Anomalies
Top Weekday Commuter Anomalies
Speed by Volume Band
Hourly Bridge Profile
Day-of-Week Bridge Profile
WGT Feeder Corridor Summary
Combined WGT Feeder Peak Timestamps
Baseline Model Sample
Detected Schema
Methodology and Caveats

Headline Metrics

Total Database Rows

132,389,534

Bridge 15-min Rows

25,767

Peak Bridge Flow

10,484 veh/hr

Average Bridge Speed

67.9 km/h

Minimum Recorded Speed

13.8 km/h

Average Baseline Delta

-0.0%

Bridge Weekday Change

-14,373/day

Inbound 7–9am Speed

46.4 → 55.1 km/h

Inbound 7–9am Flow

6,281 → 5,962 vph

Inbound Truck Share

21.33% → 18.80%

Corridor Sensors

504 and 505

Site 504 Change

-6.8%

Site 505 Change

-5.9%

Largest Peak Reduction

~19%

Visual Analysis

These charts translate the raw West Gate Bridge statistics into visual form, making the daily traffic rhythm, speed behaviour, anomaly frequency and feeder-corridor pressure easier to interpret at a glance.

Quick visual takeaway: the charts show a corridor under sustained daily pressure, with a strong morning inbound wave, a stronger afternoon outbound wave, meaningful divergence from historical norms, and clear evidence that feeder-road demand contributes materially to bridge stress.

Hourly Average Flow by Direction

Shows the daily traffic shape of the bridge. Inbound pressure dominates the morning commute, while outbound pressure becomes strongest through the afternoon and evening.

Hourly Average Speed by Direction

Shows how speed changes through the day. The chart makes the morning inbound slowdown and afternoon outbound speed deterioration immediately visible.

Average Flow by Day of Week

Confirms that weekday conditions are generally heavier than weekends, with Friday emerging as the strongest regular weekday in both directions.

Average Speed by Day of Week

Complements the flow chart above by showing that weekends are not just lighter — they are generally faster and more reliable as well.

Speed by Volume Band

This chart shows how bridge performance changes as demand rises. At higher flow bands, average speeds fall and the corridor becomes less forgiving under stress.

Share of Intervals Above Historical Baseline

A compact summary of anomaly frequency. It shows that unusually heavy traffic is not rare: 24.5% of intervals sit more than 10% above their expected baseline.

Share of West Gate Bridge intervals above historical baseline

Feeder Corridor Average vs Peak Pressure

Shows the strength of the eastbound feeder system feeding the bridge and tunnel approaches. It reinforces that congestion is generated by the wider network, not one isolated point.

West Gate feeder corridor average and peak traffic pressure

Top Combined Feeder Pressure Timestamps

Highlights the most intense feeder-corridor loading periods captured in the analysis. These timestamps help explain how extreme approach pressure can build around the bridge.

Estimated Inbound Flow Heatmap

A visual pattern map of likely inbound bridge demand by day and hour. It is useful for quickly identifying repeating daily structure and strong morning demand windows.

Estimated inbound West Gate Bridge flow heatmap

Estimated Outbound Flow Heatmap

A visual pattern map of likely outbound bridge demand by day and hour. It makes the afternoon and evening outbound wave especially easy to see.

Estimated outbound West Gate Bridge flow heatmap

Headline Metrics Chart

A compact visual summary of the page’s key headline figures, including bridge load, peak flow, average speed and low-speed stress points.

Charts are based on the published statistical summary generated from westgate_tirtl.db. Heatmaps are estimated visual composites derived from the hourly and day-of-week averages rather than a full hour-by-day matrix extracted directly from the raw database.

1. West Gate Tunnel / Bridge early comparison

Bridge-wide before/after comparison using the opening split of 2025-12-14.

Bridge comparison statement:
Average weekday bridge traffic changed from 192,875.2 vehicles/day before opening to 178,502.2 after opening, a difference of 14,373.0 vehicles/day over the available comparison period.

Interpretation: based on the available TIRTL comparison window, the bridge is carrying fewer weekday vehicles after the tunnel opened, but the measured reduction visible in this dataset is materially smaller than the larger public claim of 40,000 fewer vehicles per day.

Daily West Gate Bridge Traffic

Daily bridge totals by direction and combined total.

Weekday Bridge Flow by Time Bin

Average weekday bridge demand before and after opening.

Weekday Bridge Speed by Time Bin

Average weekday bridge speed before and after opening.

Worst Congestion Bins

Lowest average weekday speeds before and after opening.

WGT Approach Counters — Individual Site Comparison

Shown individually rather than summed, to avoid double-counting along the same carriageway.

2. Peak-window and truck follow-up

Weekday 7am–9am bridge behaviour and truck participation.

Key takeaway:
In the early operating period, the West Gate Bridge’s weekday 7am–9am inbound peak appears to have eased after the tunnel opened: average speed rose from 46.4 km/h to 55.1 km/h, while average inbound flow fell from 6,281.1 to 5,961.7 vehicles per hour. Outbound morning speeds changed much less, moving from 71.4 km/h to 71.9 km/h, even as outbound flow fell from 5,610.2 to 4,788.0 vehicles per hour.

Weekday Toll Window Flow

Average bridge flow by 15-minute bin between 7am and 9am, before and after opening.

Weekday Toll Window Speed

Average bridge speed by 15-minute bin between 7am and 9am, before and after opening.

Weekday Toll Window Truck Share

Average truck share by 15-minute bin between 7am and 9am.

Average Weekday Truck Share

Overall weekday truck share before and after opening, split by direction.

Average Weekday Trucks per Day

Estimated average weekday truck count crossing the bridge per day, by direction.

Worst Toll-Window Congestion Bins

Slowest average weekday bins between 7am and 9am in the before-and-after comparison.

3. West Gate ramp / South Wharf corridor analysis

First corridor-level work using validated TIRTL sensors closest to the SCATS-defined area of interest.

Corridor summary:
The first two validated TIRTL sensors closest to the West Gate ramp / South Wharf corridor show a modest overall decline in average weekday traffic after the tunnel-opening comparison date, and a stronger reduction at several key peak hours.

Strongest interpretation: the early pattern is more consistent with traffic redistribution and softening at selected peak hours than with traffic disappearing altogether.

Primary Corridor Sensors

504 and 505

Site 504 Coverage

631,570 rows

Site 505 Coverage

686,644 rows

Date Coverage

2025-11-01 to 2026-03-15

Site 504 Change

-6.8%

Site 505 Change

-5.9%

Largest Peak Reduction Seen

~19%

Best read

Peak pressure softened

Nearest TIRTL Matches

SCATS-to-TIRTL nearest-site matching results used to define the corridor.

Hourly Profile Weekday

Average weekday hourly flow profile for the selected corridor sensors.

Before / After Weekday

Average weekday hourly traffic before and after the split date.

Peak Before / After – Site 504

Peak-hour comparison for the first ramp-adjacent validated sensor.

Peak Before / After – Site 505

Peak-hour comparison for the second ramp-adjacent validated sensor.

Peak % Change Heatmap

Fast visual read of where the largest percentage changes occurred.

Method notes and caveats

What is established well

The bridge is carrying fewer weekday vehicles than before the opening split.
The weekday 7am–9am inbound bridge peak improved in speed and softened in volume.
Truck participation on the bridge appears to have decreased in the early operating period.
The first validated South Wharf / ramp-adjacent corridor sensors show moderate overall reductions and stronger softening at selected peak hours.

Database Overview

Database

westgate_tirtl.db

Tables found

Approx total rows

132,389,534

Date range

2025-11-01 to 2026-03-15

Distinct raw sites

302

Bridge Summary

Rows

25,767

Average volume/hour

3,750.7

Average vehicles/15m

937.7

Maximum volume/hour

10,484

Average speed

67.9 km/h

Minimum speed

13.8 km/h

Average truck share

17.32%

Maximum truck share

61.86%

Bridge Percentiles

P50 bridge flow

4,080

P75 bridge flow

5,560

P90 bridge flow

6,360

P95 bridge flow

6,872

P50 speed

73.9 km/h

P10 speed

44.1 km/h

Table Counts

bridge_15min

25,767

bridge_baseline

1,344

metadata

source_files

135

sqlite_sequence

tirtl_raw

132,362,285

Baseline Divergence Summary

Average actual VPH

3,750.7

Average baseline VPH

3,750.7

Average delta %

-0.0%

Maximum delta %

381.4%

% intervals above +10%

24.5%

% intervals above +20%

8.3%

% intervals above +30%

3.6%

Average actual speed

67.9 km/h

Average baseline speed

67.9 km/h

Direction Split

Inbound vs outbound bridge operating profile.

Direction	Rows	Avg VPH	Max VPH	Avg Speed	Min Speed	Avg Truck %
inbound	12,854	3,659.3	8,252	67.4 km/h	16.3 km/h	18.23%
outbound	12,913	3,841.8	10,484	68.4 km/h	13.8 km/h	16.43%

Peak Bridge Intervals

Top 25 bridge intervals ranked by vehicles/hour.

Date	Time	Direction	Vehicles/15m	Vehicles/Hour	Truck/15m	Truck %	Avg Speed
2025-12-16	10:00	outbound	2,621	10,484	809	30.87%	60.2 km/h
2026-01-13	15:45	outbound	2,076	8,304	364	17.53%	60.0 km/h
2025-12-19	17:00	outbound	2,075	8,300	266	12.82%	68.7 km/h
2026-01-13	7:30	inbound	2,063	8,252	373	18.08%	59.1 km/h
2025-11-14	6:15	inbound	2,062	8,248	499	24.20%	66.0 km/h
2025-11-06	18:00	outbound	2,042	8,168	293	14.35%	51.1 km/h
2025-12-08	18:15	outbound	2,040	8,160	260	12.75%	49.9 km/h
2025-11-27	6:30	inbound	2,036	8,144	527	25.88%	59.9 km/h
2025-11-20	6:30	inbound	2,033	8,132	509	25.04%	62.1 km/h
2026-01-14	16:15	outbound	2,033	8,132	268	13.18%	61.6 km/h
2026-03-04	6:15	inbound	2,031	8,124	444	21.86%	66.4 km/h
2026-01-13	16:00	outbound	2,029	8,116	314	15.48%	66.7 km/h
2026-01-20	6:30	inbound	2,014	8,056	540	26.81%	64.4 km/h
2025-12-16	6:15	inbound	2,012	8,048	501	24.90%	68.9 km/h
2026-02-26	6:30	inbound	2,012	8,048	498	24.75%	59.6 km/h
2025-11-10	6:30	inbound	2,008	8,032	481	23.95%	66.9 km/h
2026-02-19	6:15	inbound	2,008	8,032	460	22.91%	63.0 km/h
2026-01-13	15:15	outbound	2,004	8,016	396	19.76%	64.0 km/h
2026-02-23	17:15	outbound	2,003	8,012	224	11.18%	55.9 km/h
2026-03-03	16:15	outbound	2,003	8,012	321	16.03%	54.0 km/h
2026-02-09	7:45	inbound	2,000	8,000	354	17.70%	60.2 km/h
2026-02-03	6:30	inbound	1,993	7,972	503	25.24%	66.2 km/h
2026-01-14	16:00	outbound	1,991	7,964	296	14.87%	63.5 km/h
2026-03-03	16:30	outbound	1,991	7,964	305	15.32%	63.6 km/h
2026-02-09	7:30	inbound	1,990	7,960	353	17.74%	61.1 km/h

Slowest Bridge Intervals

Top 25 bridge intervals ranked by lowest observed speed.

Date	Time	Direction	Vehicles/Hour	Truck/15m	Truck %	Avg Speed
2026-01-15	17:30	outbound	2,636	106	16.08%	13.8 km/h
2026-01-15	17:45	outbound	3,216	121	15.05%	15.5 km/h
2025-12-12	19:30	outbound	3,076	132	17.17%	15.6 km/h
2026-01-15	17:15	outbound	2,948	113	15.33%	15.7 km/h
2025-12-12	19:15	outbound	3,120	142	18.21%	15.9 km/h
2025-12-12	19:45	outbound	3,032	145	19.13%	16.3 km/h
2026-02-14	18:15	inbound	3,420	63	7.37%	16.3 km/h
2026-01-15	18:00	outbound	3,300	117	14.18%	16.4 km/h
2025-11-02	14:45	outbound	1,724	57	13.23%	16.7 km/h
2025-12-18	15:00	inbound	3,104	145	18.69%	17.1 km/h
2025-11-02	15:00	outbound	2,184	57	10.44%	17.2 km/h
2026-01-23	15:30	inbound	3,708	169	18.23%	17.9 km/h
2026-02-06	16:30	inbound	3,720	156	16.77%	17.9 km/h
2026-02-14	18:30	inbound	3,688	65	7.05%	17.9 km/h
2025-12-28	8:45	outbound	1,956	50	10.22%	18.0 km/h
2026-02-14	18:00	inbound	3,652	65	7.12%	18.2 km/h
2026-01-12	12:15	inbound	3,316	210	25.33%	18.6 km/h
2025-12-12	14:45	inbound	3,804	227	23.87%	19.4 km/h
2025-12-03	16:00	inbound	4,040	195	19.31%	19.8 km/h
2025-12-20	18:00	inbound	3,560	86	9.66%	19.9 km/h
2026-01-23	13:15	inbound	3,924	232	23.65%	19.9 km/h
2026-02-06	16:45	inbound	4,216	130	12.33%	19.9 km/h
2025-12-28	20:45	outbound	2,060	40	7.77%	20.0 km/h
2025-11-30	15:45	outbound	3,116	69	8.86%	20.1 km/h
2026-01-15	17:00	outbound	3,660	149	16.28%	20.1 km/h

Slowest High-Volume Bridge Intervals

Congestion-focused low-speed list, restricted to intervals at or above 4,000 vehicles/hour.

Date	Time	Direction	Vehicles/Hour	Truck/15m	Truck %	Avg Speed
2025-12-03	16:00	inbound	4,040	195	19.31%	19.8 km/h
2026-02-06	16:45	inbound	4,216	130	12.33%	19.9 km/h
2025-11-27	15:30	inbound	4,420	208	18.82%	20.2 km/h
2025-12-04	15:45	inbound	4,720	212	17.97%	20.3 km/h
2025-12-05	14:00	inbound	4,064	237	23.33%	20.5 km/h
2025-12-05	16:00	inbound	4,252	198	18.63%	20.7 km/h
2025-12-05	16:15	inbound	4,384	178	16.24%	20.8 km/h
2025-11-21	16:00	inbound	4,048	190	18.77%	21.0 km/h
2025-12-03	16:30	inbound	4,744	200	16.86%	21.1 km/h
2025-12-12	16:15	inbound	4,784	222	18.56%	21.1 km/h
2025-12-18	13:30	inbound	4,112	248	24.12%	21.1 km/h
2026-02-06	16:00	inbound	4,380	194	17.72%	21.1 km/h
2025-12-05	14:30	inbound	4,132	223	21.59%	21.2 km/h
2025-11-26	11:00	inbound	4,284	327	30.53%	21.3 km/h
2025-12-03	15:30	inbound	4,276	218	20.39%	21.3 km/h
2025-12-12	14:30	inbound	4,368	205	18.77%	21.3 km/h
2025-11-28	15:30	inbound	4,496	190	16.90%	21.4 km/h
2025-11-14	16:45	inbound	4,516	172	15.23%	21.5 km/h
2025-11-21	16:30	inbound	4,300	195	18.14%	21.5 km/h
2025-12-18	13:45	inbound	4,184	276	26.39%	21.5 km/h
2025-12-12	15:45	inbound	4,716	230	19.51%	21.6 km/h
2025-12-18	12:45	inbound	4,584	289	25.22%	21.6 km/h
2025-11-13	15:45	inbound	4,564	226	19.81%	21.7 km/h
2025-11-28	11:00	inbound	4,144	285	27.51%	21.7 km/h
2025-12-17	16:00	inbound	4,884	213	17.44%	21.7 km/h

Top Baseline Anomalies

Top 25 intervals where actual bridge demand most exceeded the historical baseline for the same weekday and time-bin.

Date	Time	Direction	Actual VPH	Baseline VPH	Delta VPH	Delta %	Actual Speed	Baseline Speed
2026-01-01	1:15	outbound	5,420.0	1,125.8	4,294.2	381.4%	73.8 km/h	60.7 km/h
2026-01-01	1:30	outbound	4,780.0	1,017.3	3,762.7	369.9%	74.5 km/h	62.0 km/h
2026-01-01	1:00	outbound	5,604.0	1,295.6	4,308.4	332.6%	73.7 km/h	61.0 km/h
2026-01-01	1:45	outbound	3,888.0	918.0	2,970.0	323.5%	74.5 km/h	62.6 km/h
2026-01-01	0:45	outbound	5,344.0	1,363.3	3,980.7	292.0%	73.1 km/h	60.9 km/h
2026-01-01	0:30	outbound	5,880.0	1,651.1	4,228.9	256.1%	72.6 km/h	61.2 km/h
2026-01-01	2:00	outbound	3,036.0	852.7	2,183.3	256.1%	76.1 km/h	63.0 km/h
2026-01-01	2:15	outbound	2,612.0	745.3	1,866.7	250.4%	72.3 km/h	62.0 km/h
2026-01-01	2:30	outbound	2,136.0	671.6	1,464.4	218.1%	77.0 km/h	62.5 km/h
2026-01-01	0:15	outbound	5,732.0	1,876.0	3,856.0	205.5%	71.9 km/h	60.4 km/h
2026-01-01	3:00	outbound	1,816.0	621.8	1,194.2	192.1%	77.0 km/h	63.1 km/h
2026-01-01	2:45	outbound	1,920.0	662.7	1,257.3	189.7%	76.6 km/h	62.7 km/h
2026-01-01	3:15	outbound	1,648.0	604.0	1,044.0	172.8%	77.9 km/h	63.5 km/h
2026-01-01	3:30	outbound	1,512.0	573.6	938.4	163.6%	77.3 km/h	64.2 km/h
2025-11-17	0:30	outbound	3,568.0	1,390.1	2,177.9	156.7%	75.3 km/h	69.4 km/h
2026-01-01	3:45	outbound	1,540.0	600.8	939.2	156.3%	77.4 km/h	65.2 km/h
2025-11-17	0:45	outbound	2,740.0	1,186.9	1,553.1	130.8%	76.0 km/h	69.8 km/h
2025-11-19	22:00	inbound	4,644.0	2,034.9	2,609.1	128.2%	64.9 km/h	63.5 km/h
2025-11-17	0:15	outbound	3,528.0	1,603.4	1,924.6	120.0%	75.5 km/h	69.1 km/h
2026-01-01	4:00	outbound	1,480.0	687.4	792.6	115.3%	77.8 km/h	66.3 km/h
2025-12-05	0:30	outbound	3,060.0	1,422.7	1,637.3	115.1%	71.7 km/h	59.8 km/h
2025-12-07	1:15	inbound	1,948.0	918.6	1,029.4	112.1%	77.0 km/h	65.4 km/h
2026-02-16	5:45	outbound	5,136.0	2,451.8	2,684.2	109.5%	75.2 km/h	74.4 km/h
2025-11-01	0:30	outbound	4,864.0	2,336.4	2,527.6	108.2%	72.6 km/h	68.4 km/h
2025-12-16	10:00	outbound	10,484.0	5,046.9	5,437.1	107.7%	60.2 km/h	69.0 km/h

Top Weekday Commuter Anomalies

Top 25 Monday-Friday anomalies between 05:00 and 20:00, to reduce holiday and nightlife distortion.

Date	Time	Direction	Actual VPH	Baseline VPH	Delta VPH	Delta %	Actual Speed	Baseline Speed
2026-01-01	1:15	outbound	5,420.0	1,125.8	4,294.2	381.4%	73.8 km/h	60.7 km/h
2026-01-01	1:30	outbound	4,780.0	1,017.3	3,762.7	369.9%	74.5 km/h	62.0 km/h
2026-01-01	1:00	outbound	5,604.0	1,295.6	4,308.4	332.6%	73.7 km/h	61.0 km/h
2026-01-01	1:45	outbound	3,888.0	918.0	2,970.0	323.5%	74.5 km/h	62.6 km/h
2026-01-01	0:45	outbound	5,344.0	1,363.3	3,980.7	292.0%	73.1 km/h	60.9 km/h
2026-01-01	0:30	outbound	5,880.0	1,651.1	4,228.9	256.1%	72.6 km/h	61.2 km/h
2026-01-01	0:15	outbound	5,732.0	1,876.0	3,856.0	205.5%	71.9 km/h	60.4 km/h
2025-11-17	0:30	outbound	3,568.0	1,390.1	2,177.9	156.7%	75.3 km/h	69.4 km/h
2025-11-17	0:45	outbound	2,740.0	1,186.9	1,553.1	130.8%	76.0 km/h	69.8 km/h
2025-11-17	0:15	outbound	3,528.0	1,603.4	1,924.6	120.0%	75.5 km/h	69.1 km/h
2025-12-05	0:30	outbound	3,060.0	1,422.7	1,637.3	115.1%	71.7 km/h	59.8 km/h
2025-12-16	10:00	outbound	10,484.0	5,046.9	5,437.1	107.7%	60.2 km/h	69.0 km/h
2025-12-25	1:00	inbound	904.0	460.9	443.1	96.1%	78.8 km/h	66.0 km/h
2025-12-12	0:00	outbound	3,740.0	1,920.2	1,819.8	94.8%	60.6 km/h	58.1 km/h
2025-12-04	0:00	outbound	3,408.0	1,770.9	1,637.1	92.4%	41.7 km/h	59.8 km/h
2025-12-25	0:45	inbound	936.0	486.9	449.1	92.2%	78.8 km/h	66.1 km/h
2025-11-13	0:30	outbound	3,132.0	1,651.1	1,480.9	89.7%	74.0 km/h	61.2 km/h
2025-12-04	0:15	outbound	3,556.0	1,876.0	1,680.0	89.6%	41.5 km/h	60.4 km/h
2025-12-05	0:00	outbound	3,612.0	1,920.2	1,691.8	88.1%	74.3 km/h	58.1 km/h
2026-01-26	0:30	inbound	1,104.0	587.4	516.6	88.0%	78.6 km/h	68.1 km/h
2026-03-09	1:00	inbound	804.0	435.8	368.2	84.5%	79.3 km/h	69.4 km/h
2025-12-05	0:15	outbound	3,096.0	1,688.6	1,407.4	83.3%	73.0 km/h	58.6 km/h
2025-12-11	0:00	outbound	3,228.0	1,770.9	1,457.1	82.3%	60.6 km/h	59.8 km/h
2026-01-26	0:00	inbound	1,420.0	778.7	641.3	82.3%	78.3 km/h	68.1 km/h
2025-12-05	0:45	outbound	2,212.0	1,230.3	981.7	79.8%	73.7 km/h	60.5 km/h

Speed by Volume Band

This shows how speed behaves as traffic volume rises.

Volume Band	Intervals	Avg Speed	Min Speed	Avg Truck %
0-1999	7,177	68.7 km/h	16.7 km/h	22.06%
2000-3999	5,495	68.0 km/h	13.8 km/h	11.41%
4000-5999	9,058	68.9 km/h	19.8 km/h	17.40%
6000-7999	4,016	64.1 km/h	25.7 km/h	16.78%
8000+	21	61.4 km/h	49.9 km/h	20.00%

Hourly Bridge Profile

Bridge structure by hour and direction.

Hour	Direction	Avg VPH	Max VPH	Avg Speed	Intervals
00:00	inbound	795.8	2,244	66.0 km/h	536
00:00	outbound	1,833.5	5,880	65.0 km/h	532
01:00	inbound	523.7	1,996	67.6 km/h	536
01:00	outbound	1,139.2	5,604	66.8 km/h	533
02:00	inbound	435.1	1,016	69.5 km/h	536
02:00	outbound	813.3	3,036	68.5 km/h	532
03:00	inbound	521.2	940	71.2 km/h	536
03:00	outbound	666.1	1,816	69.7 km/h	533
04:00	inbound	1,034.3	2,152	73.9 km/h	536
04:00	outbound	842.9	1,480	72.7 km/h	540
05:00	inbound	3,244.2	6,688	75.1 km/h	535
05:00	outbound	1,807.1	5,168	75.6 km/h	540
06:00	inbound	5,306.0	8,248	69.8 km/h	531
06:00	outbound	3,415.0	6,136	74.9 km/h	539
07:00	inbound	5,251.6	8,252	62.0 km/h	534
07:00	outbound	4,260.4	6,876	73.2 km/h	536
08:00	inbound	5,241.7	7,956	57.2 km/h	536
08:00	outbound	4,348.1	6,584	71.5 km/h	540
09:00	inbound	5,359.3	7,684	60.5 km/h	535
09:00	outbound	4,399.7	7,480	70.2 km/h	540
10:00	inbound	5,422.4	7,304	66.9 km/h	532
10:00	outbound	4,829.3	10,484	69.4 km/h	540
11:00	inbound	5,611.9	7,432	69.0 km/h	536
11:00	outbound	5,070.6	7,056	69.3 km/h	540
12:00	inbound	5,503.4	7,420	68.5 km/h	536
12:00	outbound	5,293.6	7,100	69.0 km/h	540
13:00	inbound	5,440.3	7,576	68.5 km/h	536
13:00	outbound	5,472.0	7,000	69.0 km/h	540
14:00	inbound	5,641.4	7,648	66.8 km/h	534
14:00	outbound	5,984.3	7,760	68.0 km/h	540
15:00	inbound	5,210.8	7,068	62.0 km/h	535
15:00	outbound	6,364.0	8,304	65.2 km/h	540
16:00	inbound	5,258.7	6,848	64.8 km/h	536
16:00	outbound	6,305.2	8,132	60.3 km/h	540
17:00	inbound	5,551.1	7,580	68.3 km/h	536
17:00	outbound	6,099.8	8,300	59.2 km/h	540
18:00	inbound	4,594.3	7,728	71.8 km/h	537
18:00	outbound	5,599.0	8,168	64.9 km/h	540
19:00	inbound	3,501.7	5,596	74.6 km/h	535
19:00	outbound	4,380.4	7,628	71.1 km/h	540
20:00	inbound	2,795.1	4,768	69.6 km/h	536
20:00	outbound	3,613.4	7,328	72.6 km/h	540
21:00	inbound	2,429.7	3,828	64.9 km/h	538
21:00	outbound	3,453.8	4,976	68.8 km/h	539
22:00	inbound	1,928.1	4,644	64.3 km/h	540
22:00	outbound	3,363.0	5,624	63.5 km/h	534
23:00	inbound	1,283.3	2,904	65.4 km/h	536
23:00	outbound	2,684.4	5,452	63.2 km/h	535

Day-of-Week Bridge Profile

Bridge structure by weekday and direction.

Day	Direction	Avg VPH	Max VPH	Avg Speed	Intervals
Monday	inbound	3,585.8	8,032	68.9 km/h	1,821
Monday	outbound	3,696.4	8,160	68.8 km/h	1,813
Tuesday	inbound	3,653.9	8,252	67.4 km/h	1,822
Tuesday	outbound	3,869.0	10,484	67.7 km/h	1,809
Wednesday	inbound	3,728.4	8,124	64.7 km/h	1,811
Wednesday	outbound	4,005.7	8,132	67.6 km/h	1,819
Thursday	inbound	3,818.5	8,144	65.0 km/h	1,744
Thursday	outbound	4,069.4	8,168	65.7 km/h	1,809
Friday	inbound	3,884.7	8,248	63.2 km/h	1,824
Friday	outbound	4,126.6	8,300	66.2 km/h	1,823
Saturday	inbound	3,734.9	7,728	70.5 km/h	1,914
Saturday	outbound	3,835.4	7,428	70.9 km/h	1,920
Sunday	inbound	3,234.3	7,396	71.9 km/h	1,918
Sunday	outbound	3,319.8	7,568	71.7 km/h	1,920

WGT Feeder Corridor Summary (Sites 563–568)

Calculated correctly by summing raw class/bin rows to site-heading timestamp totals first, then averaging and taking peaks.

Site	Heading	Avg VPH	Peak VPH	Total Volume	Intervals
567	E	2,686.1	6,572.0	5,378,846	8,010
566	E	2,438.3	5,604.0	7,887,769	12,940
565	E	2,426.0	5,660.0	7,848,705	12,941
563	E	2,248.5	5,248.0	6,744,852	11,999
564	E	1,347.1	3,332.0	4,357,839	12,940
568	E	1,104.9	2,540.0	3,574,776	12,942
566	W	83.2	392.0	104	5
565	W	38.0	172.0	95	10
568	W	13.5	32.0	54	16
564	W	12.0	32.0	12	4
563	W	8.0	8.0	2	1
567	W	4.0	4.0	2	2

Combined WGT Feeder Peak Timestamps

Peak combined feeder pressure across sites 563–568.

Timestamp	Combined Feeder VPH
2026-02-03 06:00:00	28,308.0
2026-02-04 06:00:00	27,884.0
2026-02-05 06:00:00	27,832.0
2026-02-12 06:00:00	27,760.0
2026-01-29 06:00:00	27,756.0
2026-02-02 06:00:00	27,628.0
2026-01-15 06:00:00	27,584.0
2026-02-06 06:00:00	27,564.0
2026-01-30 06:00:00	27,440.0
2026-01-20 06:00:00	27,348.0
2026-02-27 06:00:00	27,280.0
2026-01-12 07:15:00	27,224.0
2026-01-21 06:00:00	27,180.0
2026-01-20 07:00:00	27,080.0
2026-01-22 06:00:00	27,068.0
2026-01-16 06:00:00	27,060.0
2026-02-06 06:15:00	27,020.0
2026-01-21 07:30:00	26,988.0
2026-02-11 06:15:00	26,960.0
2026-02-10 06:15:00	26,888.0
2026-01-20 06:15:00	26,792.0
2026-01-22 06:15:00	26,736.0
2026-02-04 07:15:00	26,712.0
2026-02-07 14:30:00	26,632.0
2026-01-21 06:15:00	26,596.0

Baseline Model Sample

First 40 rows from bridge_baseline to show the structure of the model.

Direction	Day	Time Bin	Samples	Avg VPH	Median VPH Eq.	P10 VPH Eq.	P90 VPH Eq.	Avg Truck %	Avg Speed
inbound	Sunday	0:00	20	1,658.6	1,668.0	1,350.8	2,049.2	5.03%	63.9 km/h
inbound	Sunday	0:15	20	1,451.4	1,486.0	1,161.6	1,665.6	5.31%	64.3 km/h
inbound	Sunday	0:30	20	1,320.8	1,314.0	1,022.0	1,453.6	5.65%	64.2 km/h
inbound	Sunday	0:45	20	1,135.4	1,096.0	980.4	1,343.6	5.53%	64.5 km/h
inbound	Sunday	10:00	20	4,914.6	4,960.0	4,400.0	5,575.2	6.53%	75.6 km/h
inbound	Sunday	10:15	20	5,309.2	5,498.0	4,716.0	5,849.6	6.25%	75.1 km/h
inbound	Sunday	10:30	20	5,651.6	5,858.0	4,968.8	6,175.6	6.16%	74.8 km/h
inbound	Sunday	10:45	20	5,698.6	5,820.0	5,107.2	6,329.2	6.31%	74.7 km/h
inbound	Sunday	11:00	20	5,852.2	6,000.0	5,392.0	6,692.8	6.35%	74.5 km/h
inbound	Sunday	11:15	20	6,198.0	6,402.0	5,581.2	7,148.8	6.11%	74.1 km/h
inbound	Sunday	11:30	20	6,230.2	6,440.0	5,795.6	7,089.2	6.13%	73.0 km/h
inbound	Sunday	11:45	20	6,029.6	6,268.0	5,460.0	6,836.0	5.86%	72.3 km/h
inbound	Sunday	12:00	20	5,925.2	6,122.0	4,919.2	6,684.8	6.11%	70.7 km/h
inbound	Sunday	12:15	20	5,998.2	6,162.0	5,352.0	6,652.4	5.68%	70.4 km/h
inbound	Sunday	12:30	20	6,018.8	6,170.0	5,379.2	6,832.0	5.80%	71.5 km/h
inbound	Sunday	12:45	20	5,699.4	5,738.0	4,920.0	6,702.8	6.14%	73.4 km/h
inbound	Sunday	13:00	20	5,676.8	5,806.0	4,871.2	6,379.2	6.03%	73.1 km/h
inbound	Sunday	13:15	20	5,616.2	5,866.0	4,640.4	6,506.8	6.18%	73.2 km/h
inbound	Sunday	13:30	20	5,584.8	5,898.0	4,655.2	6,212.4	6.20%	73.3 km/h
inbound	Sunday	13:45	20	5,580.0	5,744.0	4,856.4	6,558.0	6.59%	73.2 km/h
inbound	Sunday	14:00	20	5,508.6	5,702.0	4,727.2	6,257.2	6.43%	73.2 km/h
inbound	Sunday	14:15	20	5,488.8	5,658.0	4,513.2	6,316.8	5.94%	72.5 km/h
inbound	Sunday	14:30	20	5,490.0	5,660.0	4,772.8	6,209.6	6.46%	72.7 km/h
inbound	Sunday	14:45	20	5,461.6	5,620.0	4,908.0	6,154.0	6.20%	72.3 km/h
inbound	Sunday	15:00	20	5,292.0	5,474.0	4,692.8	5,786.8	6.38%	73.2 km/h
inbound	Sunday	15:15	20	5,402.0	5,616.0	4,788.4	6,091.6	6.12%	73.2 km/h
inbound	Sunday	15:30	20	5,580.4	5,674.0	4,940.0	6,400.8	5.92%	73.0 km/h
inbound	Sunday	15:45	20	5,418.8	5,576.0	4,760.4	6,106.4	6.10%	72.5 km/h
inbound	Sunday	16:00	20	5,267.8	5,398.0	4,707.6	5,929.6	6.24%	73.2 km/h
inbound	Sunday	16:15	20	5,413.6	5,620.0	4,991.2	5,928.0	6.02%	73.4 km/h
inbound	Sunday	16:30	20	5,557.6	5,688.0	5,128.0	6,261.6	5.79%	73.8 km/h
inbound	Sunday	16:45	20	5,490.6	5,584.0	5,070.4	6,267.2	5.97%	73.1 km/h
inbound	Sunday	17:00	20	5,486.8	5,600.0	4,844.4	6,383.6	6.04%	73.5 km/h
inbound	Sunday	17:15	20	5,582.6	5,770.0	5,000.4	6,441.6	5.80%	73.3 km/h
inbound	Sunday	17:30	20	5,560.8	5,526.0	5,010.0	6,450.4	5.73%	72.9 km/h
inbound	Sunday	17:45	20	5,200.8	5,352.0	4,601.2	6,161.2	6.15%	73.2 km/h
inbound	Sunday	18:00	20	4,810.4	4,828.0	4,386.4	5,456.8	6.50%	73.6 km/h
inbound	Sunday	18:15	20	4,683.6	4,604.0	4,242.8	5,492.0	6.54%	73.3 km/h
inbound	Sunday	18:30	20	4,361.0	4,272.0	3,856.0	5,006.8	6.57%	74.3 km/h
inbound	Sunday	18:45	20	3,961.0	3,980.0	3,163.2	4,648.0	6.47%	74.7 km/h

Detected Schema

bridge_15min

ts_local, date_local, time_bin, direction, site, heading, vehicles_15m, vehicles_per_hour, truck_15m, truck_pct, avg_speed_kmh, row_count

bridge_baseline

direction, day_of_week, time_bin, sample_count, avg_vehicles_15m, median_vehicles_15m, p10_vehicles_15m, p90_vehicles_15m, avg_vehicles_per_hour, avg_truck_pct, avg_speed_kmh

tirtl_raw

raw_id, source_file_id, ts_local, date_local, time_bin, site, heading, vehicle_class, speed_bin, volume

Methodology

This analysis is based on raw TIRTL (Traffic Infrared Traffic Logger) data collected across the West Gate Bridge corridor. All statistics are generated directly from the underlying dataset without manual adjustment.

Data Source

Database: westgate_tirtl.db
Total records: 132,389,534
Date range: 1 Nov 2025 → 15 Mar 2026
Coverage: 302 traffic monitoring sites

Processing Method

Raw detections aggregated into 15-minute intervals
Converted to vehicles per hour (VPH) for comparability
Separated by inbound and outbound bridge direction
Truck share calculated from classified vehicle data

Baseline Model

A time-aware baseline was constructed using historical averages for each day-of-week and 15-minute time interval.

Each interval compared against its historical equivalent
Allows detection of abnormal traffic demand
Used to identify peak anomalies and congestion events

Definitions

Vehicles/hour (VPH): Standardised flow rate derived from 15-minute counts
Baseline: Expected traffic for the same day and time
Anomaly: Deviation from baseline conditions
Truck %: Share of heavy vehicles in total flow

Limitations

Sensor-based system — subject to normal measurement variation
Analysis period limited to Nov 2025 → Mar 2026
External factors (incidents, weather) not explicitly modelled