Know your limit

TfL is trialling Intelligent Speed Adaptation technology to assess its impact on reducing collisions in the capital

Last year in London, speed was a factor in over 3,000 personal injury collisions. The London Road Safety Unit (LRSU) has been working on innovative road safety measures in recent years and one of these systems is called ISA – Intelligent Speed Adaptation.
    
Intelligent Speed Adaptation is a technology which people can use to establish the correct speed limit and, if desired, it will assist drivers to keep within those speed limits.
    
Modern cars provide lots of information to the driver, such as the air temperature or fuel efficiency, but up to now not the one vital piece of information that the driver really needs – the current speed limit. With ISA this is now possible in London.

Reducing collisions
The TfL ISA project takes this one step further and connects to the vehicle electronics such that the driver has the option to stop the engine accelerating when the speed limit is reached.
    
Research by the University of Leeds estimated that even an advisory ISA system would reduce collisions by about ten per cent in London. Given there were 23,116 crashes in London in 2008, ISA has huge potential to improve road safety. The extent to which ISA becomes the norm depends on the demand in the market place. If drivers want it, it is there for them to use it.
    
The project has involved the digital mapping of all speed limit signs on London’s roads – and maintaining this information. TfL has made the map freely available on a web site. By incorporating the map, sat navs can now communicate the accurate speed limit to a driver and warn them if they exceed the speed limit. We believe all GPS devices could be modified to take advantage of the digital speed limit map. Although current maps, such as those found in commercial satellite navigation units do include some speed limit information, this generally is not very accurate.

ISA technology
The two types of ISA technology which we are now trialling are Advisory ISA which simply displays the speed limit inside the car. Voluntary ISA is then an optional extra which allows the driver to turn on a speed limiting capability in the car.
    
Advisory ISA uses standard GPS, similar to a commercial satellite navigation device, with a digital speed limit map loaded into the device. The vehicle uses this map to determine which road it is on, and therefore which speed limit applies.
    
Voluntary ISA requires further, speed limiting equipment to be fitted to the vehicle. If the driver has elected for the system to do so, the system interacts with the engine to assist the driver to keep below the speed limit. If not, the system simply displays the speed limit to the driver as in the Advisory version.
    
We are looking at having 20 TfL fleet vehicles as part of the six month trial which should conclude at the beginning of next year. Initial feedback has been very positive and we are already acting on some of the areas that are not so popular. The ISA screen, for example, will undergo a re-design as people have found the ‘smiley face’ a little annoying. This will however remain as a user configurable option.
    
Other initial findings are that we have found many people who have been sceptical about the idea and initially feel hostile, once having driven the vehicle, become ‘converts’.  Interestingly, the much feared ‘loss of driver control’ is not an issue as drivers realise that they are still very much in control.

Road safety benefits
So what do we think the road safety benefits are?
    
It is estimated that if at least two-thirds of Londoners used the advisory ISA system, the number of road casualties in London would be reduced by ten per cent. In London you wouldn’t need to fit every vehicle – if two out of three cars on the road have it then the one car which does not is being influenced by the other two anyway. This is not necessarily true elsewhere in the country where vehicle densities are lower.
    
According to the RoSPA Road Safety Factsheet (August 2006) driving too fast for the conditions causes, or contributes to, one third of road crashes and:

• Hit by a car at 40 mph, nine out of ten pedestrians will be killed
• Hit by a car at 30 mph, about half of pedestrians will live. 
• Hit by a car at 20 mph, only one out of ten pedestrian will be killed.

With Advisory ISA it has been estimated there could be up to 13 per cent reduction of collisions, and 18 per cent KSI and 24 per cent reduction in fatalities. With Voluntary ISA that estimate goes up to 18 per cent collision reductions, 26 per cent KSI and 32 per cent reduction in fatalities.

That is a safety benefit worth pursuing.

Increasing compliance
Another key benefit to drivers is increased compliance with the speed limit. This reduces a driver’s risk of points on their license or fines from speed cameras and traffic police.
    
When driving at higher speeds on motorways, modelling also predicts that ISA will reduce fuel consumption, and more generally slower speeds result in smoother network flow.
    
Once the trial has taken place, TfL will assess the results and report to the Mayor in Spring 2010. Based on that report, we believe other authorities, such as Southwark Council, may place an order with manufacturers for ISA.
    
TfL’s role is to test the product and publicise the results of that testing, so that other authorities, organisations, and indeed individuals can decide if they are interested in using ISA. We are doing our bit, and it will be interesting to see what happens next.