All you wanted to know about Traffic Lights  26.10.10

Report on the recent Cyclox meeting

Mike Best is the county council traffic signals engineer and is responsible for the 378 sites in Oxfordshire, of which only 147 are controlling traffic junctions – the rest are pedestrian crossings.
There were only about 15 people at the meeting but it was so enjoyable we felt Mike should be invited again to a wider audience.

Cyclists have all noticed the oddly shaped tarmac patches in front of traffic lights – we learned that the oblique (half-chevron) ones are shaped to improve capture of a passing vehicle and trigger the lights whereas the oblong patches (scoot loops) detect stationary vehicles to judge the amount of traffic and therefore how long a light will stay green.

We were firmly on the side of the pedestrian when we learned that crossings will wait up to 30 seconds until a gap occurs in the traffic – ‘if there is a gap we don’t need the lights’. Many crossings have sensors looking down at the crossing and only allow the traffic to move when people are safely across. Others only change to the green man if someone is still standing next to the light. The crossing on High St is said to be on red to both pedestrians and traffic by default, but none of us had seen this situation, which Mike assured us was just because we were approaching it.

98% of all the lights in Oxfordshire are linked to the central control by a phone line and automatically report any fault. If the fault is for both directions to be green the lights will automatically close down. All lights are inspected six monthly at an annual cost of £777 per site. Siemens have the contract and are replacing the halogen bulbs (50W) with LEDs (9W in the day, 3W at night) – about 15% have been converted already. All light boxes are changed every 10 years.

We heard about the cameras around Oxford – there is a central monitoring office in Speedwell St looking at pictures from the UTMC (urban traffic monitoring control) and ANPR (automatic number plate recognition) cameras. The latter is encrypted and the information deleted after two hours so couldn’t be used for solving a crime. The ANPRs from Swindon to Oxford were funded by BMW to help them get their deliveries ‘Just in time’.

Most importantly from our point of view – traffic lights are definitely intended to detect a cyclist approaching and if one doesn’t you should report it to Mike: Tel 01865 815775 or traffic.signals@oxfordshire.gov.uk. There are live traffic updates based on the ANPR at www.oxfordshire.gov.uk/travelinformation

We thanked Mike enthusiastically and will never look at a traffic light in quite the same way again.

Andy Chivers

Cyclox