Speed humps cause road deaths

Hintza

The State of Colorado seems to be concerened about the use of speed bumps!

http://www.ci.englewood.co.us/Index.aspx?page=214

What are speed bumps? Speeding on residential streets is a common concern reported by citizens. Speed bumps are often requested because they are perceived as a quick and effective solution to speeding. Speed bumps are ridges of pavement, usually 3 inches high, placed across a roadway. Theoretically, the bumps are intended to be uncomfortable to drive over if crossed over too quickly, and should force cars to slow down as they pass over them. However, speed bump installations have been associated with maintenance, safety, and liability concerns.

Are speed bumps safe? Tests of speed bumps raise questions about their safety and effectiveness. Test results indicate that:

• Speed bumps do not significantly reduce vehicle speeds once the vehicle leaves the speed bump.
• Speed bumps present a potential hazard to all vehicles and an immediate danger to bicyclists, motorcyclists, and emergency vehicles.
• Traffic volumes increase on adjacent streets since drivers tend to avoid streets with speed bumps.

What about Liability? Results of various studies have raised concerns about the potential dangers of speed bumps. Speed bumps are not recognized by the State of Colorado as an official traffic control device. Injuries caused by speed bumps may result in significant additional liability for the City. For these reasons, the City of Englewood does not use speed bumps on public streets and alleys.

BargainGalore

Surely potholes can cause damage too I am sure most of us know over the years potholes have got worse and most likely to continue given budget constraints

dacouch

Speed Humps = Greater Risk

"Speed trapped", Orlando Weekly, Jeffrey C. Billman, August 17-23, 2000

"...the 259-page master's thesis recently written by Austin, Texas, Assistant Fire Cheif Les Bunte. In "Traffic Calming Programs and Emergency Response: A Competition of Two Public Goods," the 27-year firefighting veteran makes a startling observation." "Using a detailed formula developed by Boulder, Colo., scientist Ray Bowman, Bunte determined that in Austin, at least 37 people would die because of slower emergency response time for every one life saved by slower traffic. Since Bunte took into account only deaths from sudden cardiac arrest - and not from delayed fire response or any other condition - that number could be higher."

Sput2001

Not 'cannot' - try 'can not'

Cannot is a perfectly acceptable spelling. In fact, many authorities prefer it to can not.

flyingscotno1

I did a dissertation a good while back on this whilst at uni. Frankly the evidence is distorted by the driving lobby on one side and the anti-car on the other so it is difficult to read between the lines and get independent evidence.


The type mentioned (2 or 3 squares across) are speed cushions. They were invented by the Germans, the original name is 'Berlin Pillows'! By contrast the real inventors of traffic calming were the crazy Dutch!

I think there is a case for them, but they need to be used correctly, but many councils mis-use them as a general device with "if we put them down they will cause 10% accident reduction". Same with "new development along the road so stick in speed humps to placate residents". Traffic engineering is a science and not a book of measures, something neglected by some local authorities. Equally design can be poor- too steep, too high, too wide and it can be hard to get the right profile, hence pre-cast units are popular.

Saying that, used in the correct areas they can stop rat-running (sometimes firepaths or bus only roads are better) and reduce traffic speeds. They do increase pollution, however you need to remember this is drivers actually doing what they shouldn't - in a highway code your expected to remain a constant speed! Accident results are encouraging, but you need to take into account a number of statistical factors!

I never encountered much evidence looking at tyre wall damage. Tyre damage was more related to hitting them at speed, the main problem was damage to suspension. With cushions problems with tracking were mentioned- people in cars staddling them getting forced wheels forced wide. Even with suspension parts one mechanic did mention that some of it is attributed to 'them not making them like they used to', and that some of the suspension parts being used are of lesser standards. 46 tyre problems is probably not statistically noticeable given the millions of tyres going over humps every day- it may be that tread wears out far before any damage to sidewalls. I'd imaging kerbing causes higher damage- but it is interesting never the less.

What is noticeable in my research, was that in local areas near me, traffic accidents and speed humps were mainly located in council estates (bar new developments where developers also install them as a matter of course).

This suggests to me- 60's road design was poor / council estates typically have more pedestrian volumes, more kids out and about. We found that looking at nearly all the places in the council areas built at that time had road humps.

sickparrot

I have to cycle through two areas of spped pillows on my daily commute, and they terrify me. They don't make a jot of difference to traffic speed, provided the cars either swerve into the middle of the road or pull right into the side in order to pass them cleanly. How is this 'safe'?

Either build them all the way across or not at all.

My own personal preference is for not at all and put more surprise speed traps out. Anybody caught speeding on residential roads should be banned instantly in my book

Rallydriver

All the components in a cars suspension will have a design life. Components being tyres, springs, dampers, bushes, balljoints. All these components will have a decreased lifetime if the vehicle goes over speed humps regularly, there is no getting away from this fact.

Usually, because most drivers are ignorant to the workings of their vehicles and don't do any regular checks, the only time wear is picked up on a vehicle is at the MOT once a year. erm.. I'm tired and I've forgotten where I'm going with this.

Next point. Not only do you have to consider the design of speed humps and cushions, but the poor state of maintenance of them also. Of all the speed cushions in this area, I can't think of one which isn't breaking up at the sides.

Generally, the faster you go over a speed hump/cushion, the greater the forces that have to be absorbed by the suspension components.
Hence I slow down to crawling pace for each speedhump, however this does annoy any motorists following me. If its a long road with many speed cushions then it can lead to a queue of 20 odd peed off drivers yo-yo-ing between the bumps - but I feel no obligation to cause needless wear to my own car just to appease a few following drivers.