The A14 is a strategic route of national importance which connects the motorways of the Midlands and the North of England to the City of Cambridge, East Anglia, the ports of Felixstowe and Harwich and the M11 to the south.
Many sections of the A14 are currently operating close to capacity, with an average of 65,000 to 85,000 vehicles per day using the route. Up to 25% of the traffic is heavy goods vehicles, which is about twice the national average for this type of road. Consequently, the A14 experiences severe congestion, particularly during peak hours, which results in unreliable journey times.
Z/Yen was asked to use PropheZy, the world-class risk/reward prediction engine, to predict journey times on the A14 in an attempt to help alleviate conditions.
We were provided with historical journey times from the Highways Agency dating back one year for various segments of the A14 as well as supplementary information on events such as accidents and roadworks which may have affected journey times.
In order to conduct our trials we picked two specific sections of road (code named AL2282 and AL229) which were 6.9km and 1.7km in length respectively. We built a model around the historic data for these segments, each model taking into account approximately 30,000 journeys. We then used the models to predict 2,880 journey times for the most recent month for which we had known data (September 2011). To make the predictions we split all the journey times into five second bands and predicted the band into which new journeys would fall. In building the models we included the following predictive parameters for each journey made.
Segment AL 2282: Most of the historical journey times fell between 200 – 350 seconds. The journey times within this range were split into 30 distinct five second bands. The table below lists the number of cases in which PropheZy either predicted the correct band or was correct within one to five bands.
| N | % | |
|---|---|---|
| Correct | 525 | 18.23% |
| Within 1 band | 1,366 | 47.43% |
| Within 2 band | 2,028 | 70.42% |
| Within 3 band | 2,413 | 83.78% |
| Within 4 band | 2,600 | 90.28% |
| Within 5 band | 2,689 | 93.37% |
| Total | 2,880 |
Most of the historical journey times for AL 229 took between 55 – 115 seconds. In this case, all the journey times within this range were split into 12 bands.
| N | % | |
|---|---|---|
| Correct | 1,019 | 35.38% |
| Within 1 band | 2,257 | 78.37% |
| Within 2 band | 2,593 | 90.03% |
| Within 3 band | 2,751 | 95.52% |
| Within 4 band | 2,843 | 98.72% |
| Within 5 band | 2,862 | 99.38% |
| Total | 2,880 |