Trucker's view of calming in the U.K.

By: Gordon Pye
Date: 1996-09-09

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To use fuel efficiently, the driver of a heavy vehicle needs to store the energy contained in the vehicle. Traffic calming is perhaps the greatest waste of fuel ever devised. One new roundabout, causing an average speed reduction of 30 Kph, traversed five times loaded at 32.5 tonnes, and four times at 11.5 tonnes, used on average 2 gallons extra fuel per day. This can be proved by mathematical calculation, but I have never seen the equations in any text book.

I have undertaken a rough calculation of the extra fuel used by causing a heavy vehicle to stop or slow. The roundabout calculation shows that fuel consumption is doubled over a certain road section from the start of braking, to the end of acceleration. This will be true for all vehicles forced to stop or slow. The same principle applies to all vehicles if the stored energy has to be wasted through the brakes.

I have recently heard that all new or improved major roads in Lancashire must have roundabouts at all junctions with less than 1 km vision in both directions. The roundabout recently constructed on the A59 near Clitheroe is so tight for Heavy Goods Vehicles (HGVs), that it will reduce speed to under 20 Kph for vehicles traveling up grade. It is also guaranteed to increase congestion, therefore using extra fuel. Even though the road is dual carriageway, the roundabout has only one true lane through it, unless everyone drives a Nissan Micra.

If anyone had deliberately set out to design a death trap for cyclists, it is doubtful whether they could have made a better job of it. Drivers at a nearby cement works are experiencing vehicle stability problems at low speed in the eastbound (empty) direction. Their union representatives have asked the company to contact the local highway authority in an attempt to get the roundabout modified into a safer layout.

Miles per Gallon is not a true measure of fuel consumption. The true measure is grams per kilowatt hour, as used by transport engine manufacturers. The total amount of time under power is the factor which determines Mpg. Almost all internal combustion engines are most efficient at or near full load. This is because the heat lost through cooling and the exhaust is almost constant under any load condition.

Developments such as power steering, air conditioning and even electric windows all consume extra fuel. Air conditioning is perhaps the most environmentally damaging development, as it consumes a vast amount of extra fuel. Average family cars fitted with power steering may use up 10% more fuel than non fitted vehicles. The addition of air conditioning may increase fuel consumption by a further 15% or more?

Factors such as these can make recent theoretical improvements in thermodynamic and emission performance quite meaningless. Almost all new cars come with power steering and or air conditioning as standard. If the public were aware of the extra pollution caused by these extras, perhaps the manufacturers would be forced to abandon them as standard.

Road safety is usually the reason used to justify traffic calming schemes, but most are designed to slow the average family car. To the HGV driver, most new junction layouts cause more potential safety problems than the ones they replaced. Road design appears to have more to do with the need to accommodate standard kerb (curb) components, than the physical needs of long vehicles. Modern road design takes no account of the turning space that a long or articulated vehicle needs. The junctions and roundabouts are quite adequate for the needs of a car, but the lanes are usually impossible for HGV's or buses to follow. Apart from causing additional safety problems for other road users, bad road design also increases wear and tear, driver fatigue, and thus the ultimate safety of the vehicles themselves. I have been reliably informed that new traffic calming under rail bridges is largely responsible for the recent high number of bridges hit by high vehicles? The present situation is probably the result of a whole generation of road designers being taught the perverse theory that, "making roads more dangerous makes them safer."

Inappropriate traffic calming on routes frequently used by HGV's and buses causes additional problems. Once wide roads which once caused few problems are now filled with pinch points and traffic islands. Most new roads are a series of traps to catch cyclists and incompetent car drivers.

The specified minimum safe distance from the kerb was 18 inches when I passed my HGV test in 1982 . This distance is impossible to achieve where traffic calming measures exist. Traveling close to the kerb is bad for pedestrians, especially when pools of water form in holes or hollows.

The A59 at Copster Green between Preston and Clitheroe carries a large amount of extra HGV traffic from the cement works and roadstone quarries at Clitheroe, and the quarries in the Craven area of North Yorkshire. The road was improved during the 1960s and did not require resurfacing until about 1990. Two years ago, Lancashire County Council introduced traffic calming measures at Copster Green. In addition to a 40 Mph speed limit, several traffic islands were built into the centre of the wide road.

Since the introduction of central traffic islands, all HGVs are forced to travel close to the nearside kerb. This has caused excessive damage to the nearside of the road in both directions. Almost all the drain grates have been pounded well below the road surface and the surface is cracking up next to the kerbs. This creates additional dangers for cyclists.

In just a couple of years, the traffic islands at Copster Green have caused the same amount of damage which one would expect after about 15 years or more for a similar wide road. The extra maintenance of the carriageway must place extra demands on natural resources. Patching roads usually means that more material than needed is ordered. The spare (usually at least a ton) ends up being tipped back at the quarry, unless the driver can find someone who has a use for it, then only if its the last load of the day.

Traffic Calming encourages lunatic drivers to attempt an overtaking maneuver on the approach to pinch points, or roundabouts . It is impossible for vehicles to follow a true safe line through any of the obstacles after the road alleged safety improvements. Road design is a major factor in overall road safety, but is seems as though no one is prepared to take this important factor seriously.

Many accidents involving goods vehicles are a direct result of poor road design. Adverse cambers and other ideas designed to slow traffic are built in to almost all new roads.

Road design appears to be immune from scrutiny by accident investigators, even though it is the probable cause of many accidents. Most new road junctions are designed to cut the speed of vehicles using them. However, designing roads with impossibly low safe speeds is counter productive in the case of heavy goods vehicles. Being crushed by a goods vehicle ( or its load ) traveling at 5 Mph leaves you just as dead as one traveling at 50 Mph. Modern road layouts almost all incorporate features which can set up a pendulum effect in high vehicles and lead to slow speed roll-over. The driver can counteract this effect by use of the accelerator to provide a force to cancel out the effect. Being forced to apply the brakes, or cut the accelerator at the wrong moment during the pendulum cycle is extremely dangerous.

Continual braking and accelerating also causes the brakes of HGVs to rapidly overheat and "fade" thus significantly increasing the stopping distance in an emergency. This factor is compounded on vehicles fitted with ABS, but that's another story.

Air pollution could also be reduced by reversing the present theory of traffic management by traffic calming. In many cases this would cost very little as it mainly involves altering the phasing of traffic lights. The replacement of all small diameter roundabouts on major roads would also produce a useful reduction in emissions from all vehicles. Part time traffic signals and "free give way" left turns could replace many current roundabouts and other permanently controlled junctions, without a significant reduction in safety.

The recent development of speed cameras offers a unique opportunity to depart from the use of potentially dangerous road layouts to control the speed of vehicles. Roads could once again be laid out to suit the true safe turning characteristics of vehicles, as demonstrated when snow obscures the lane markings. By getting rid of the need for small roundabouts and any other forms of traffic calming, land, fuel, tyre wear, and other vehicle maintenance is saved; road maintenance will also be less frequent and easier. Thus we would likely see cost savings for everyone and benefit to the environment all round.

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