Driver Skill Can Exorcise Phantom Jams
Research from Bristol University has drawn attention to phantom traffic jams, but the ABD is critical of both recommended solutions and AA advice.
ABD spokesman Nigel Humphries explains:
“The problem of ‘phantom jams’ on motorways is well known. It takes only one small action to create a ripple effect of braking cars which escalates as it moves back down the line, eventually halting traffic.” 1
Dr Eddie Wilson, author of the report and Andrew Howard, the AA's road safety spokesman are quoted as recommending drivers travel at 50MPH
instead of 70MPH
to solve the problem.2
Dr Wilson also advises drivers to “avoid changing lanes” and to “try to stay in the same lane”.3
Nigel Humphries continues:
“This is foolish advice. It positively encourages some of the practices that cause phantom jams such as travelling too slowly for the conditions and hogging the centre or outer lanes causing other drivers to slow or change lanes to pass.
All drivers have a duty to ensure that they are not contributing to congestion or phantom jams and there is much that they can do. We desperately need an education campaign in the UK advising drivers on motorway driving but unfortunately the government has been persuaded by vested interests that expensive technology (variable speed limits) is the only solution to congestion.
Good motorway drivers read the road far ahead, and can see the ripple of stationary traffic coming towards them. If you slow down early and try to avoid stopping, you ‘Kill the ripple’. I've succeeded in doing this on my own on the M42 — just think how effective it could be if more drivers were encouraged to behave in this way — yet the ‘experts’ trotted out to discuss the Bristol report failed to mention this obvious point.”
The ABD offers the following additional advice to drivers to prevent phantom jams:
- Maintain good lane discipline. If you are not overtaking move to the leftmost lane. If you are blocking an outer lane other drivers have to either slow down or change lane to pass you.
- Try to avoid braking by keeping a safe distance. If the car in front brakes this gives you time to just ease off a little and avoid a ripple effect. It is quite possible to 'iron out' ripples this way.
- When leaving the motorway try not to slow down until you are in the slip road. This avoids disturbing traffic flow.
- When entering the motorway accelerate to the speed of traffic. Never enter at a speed slower than traffic in lane one. It causes braking and needless lane changing.
- Don't drive unnecessarily slowly. Trucks are electronically governed to 56MPH. If you travel slower than this speed you will create congestion as they move out to pass you. If you don't feel comfortable driving above 50MPH then don't use the motorway.
- Plan lane changes to cause no disruption to traffic flow. When overtaking accelerate briskly to match speed of traffic in the lane you are moving into. When moving back find a gap large enough that you can slot into without braking.
- Remember it takes just one driver to block a motorway. Don't be that driver. Think about the effect of your actions on traffic behind you. Ask yourself if other drivers are having to alter course or slow down because of your position or speed.
By following the above advice drivers can help to ensure that the road space we have is used to maximum efficiency. This helps safety, saves fuel for all and cuts pollution. Whilst we need more motorway capacity much could be done with education to increase efficiency. This should be a priority rather than expensive and ineffective variable speed limits which make a poor attempt at ironing out ripples after they are already well established. It is notable that Paul Clark, the Road Safety Minister recently become the first serving Department for Transport Minister to take a driving assessment with the Institute of Advanced Motorists (though regrettably not the full IAM test). Apparently he found their tips on using mirrors and maintaining lane discipline of the most use. 4
NOTES FOR EDITORS
1. You Tube — Shockwave traffic jams recreated for first time
2. Daily Mail
3. BBC One Show 2nd April (20 mins in) [link will expire]
4. IAM — Road Safety minister takes IAM Drive Check
Notes for Editors about the ABD