SETTING NEW LIMITS
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Coach operators must by law fit their vehicles with speed limiters and although they don't come cheap, specialists like Tappins Coachworks aim to make the process easy and cost effective.
• With legislation on speed limiters now in force, coach operators must face up to fitting them to most, if not all, of their vehicles.
Official Lucas Kienzle speed limiter agent Tappins Coachworld hopes it can make the extra work as straightforward as possible for customers who may be apprehensive about the process.
The Didcot-based firm is no stranger to coach operations. It is one of the top coach and coach-holiday operators in Britain running 56 vehicles. Most are Volvos, but it also has 13 Bedfords, six Leyland Leopards, two Leyland Nationals and two Caetano Optimos. Most of the bodywork is Plaxtons.
"Our future purchasing policy is for Volvo chassis," says engineering director Robert Tappin. Tappins has recently moved to a new site just outside Didcot. Its brand new engineering facilities are designed to accommodate both its own requirements and the fitting of speed limiters to other vehicles. The company has fitted them to its own chassis, so it can discuss the advantages and methods of fitting with customers.
"We have the advantage of being an established operator — we can put out information from the operators' point of view," says managing director Paul Tappin, "and we have contacted every operator in the South Midlands and Thames Valley. We will even collect and deliver. We can fit a limiter in a day, though the more complicated coaches may take a little longer."
TEST DRIVES
He says rental companies and agencies have also been contacted: "We will fit limiters on any commercial vehicle," he points out. Tappins even offers test drives so potential customers can try the speed limiters in action.
"We have found instant fuel savings in our own fleet and our drivers fully approve of the limiters," says Robert Tappin. "In fact, those still waiting to have them fitted want the job done as soon as possible." By the end of this season Tappins will be able to quantify the fuel savings — the firm uses a computer based fuel management system, which should provide an accurate indication of savings. Already some hauliers are reporting savings of almost 20% in fuel consumption.
The new law only affects coaches. A 'coach' is defined as a large bus constructed or adapted to carry more than 16 passengers, weighing more than 7.5 tonnes and with a maximum speed exceeding 70tnph.
If your coach was first used on or after 1 April 1989 it has to have a limiter fitted. If first use was between 1 April 1984 and 31 March 1989 you have till 1 April 1990. If it was between 1 April 1974 and 31 March 1984, the speed limiter must be in place by 1 April 1991. Older coaches are exempt.
The role of the speed limiter is quite simple — to restrict the speed to 70mph. Any other function is purely optional. The law again requires that a plate is put "in a conspicuous position" to say that a speed limiter had been fitted. Tappins fits this to the windscreen so it does not interfere with the driver's vision, and can also be seen easily from the outside.
Paul Tappin is a little apprehensive about operators leaving it to the last minute — he says it is not a good idea to leave it till the end of March 1990 to have limiters fitted.
Lucas Kienzle says it was the first in Britain, in 1982, with an all-electric limiter. It consists of an electronic control and an electric actuator. The limiter senses not only road speed but acceleration.
As the regulated speed is approached, the reaction of the speed actuator is adjusted accordingly and so cutting out any hunting. It can he fitted to both mechanical and electronic tachographs and the cost is around £500.
ELECTRIC MOTOR
The compact actuator is small enough to be mounted close by, or directly on to, the injection pump. In it is an electric motor and gearbox driving a trunnion. The trunnion's push-pull movement is transmitted to the fuel pump lever, which is pivoted so it is under the control of either the actuator or the normal accelerator linkage.
When the vehicle meets an incline, the control instructs the actuator to increase the fuel requirement. Because the actuator is so small it can be mounted on light vans — a 12-volt version is available — making the limiter suitable for minibuses. It doesn't even have to be fitted to a tachograph.
Lucas has developed test units which enable the controlled speed to be set and checked either on the bench or when the vehicle is stationary. This is one advantage of having a competent firm like Tappins fit the limiter — it calibrates and seals the unit, so that when the annual inspection comes round all that has to be looked for is a seal that has not been tampered with. There is an optional intermediate speed-hold switch which allows lower top speeds to be selected by the driver. This is not a cruise control because the driver still needs to keep a foot on the accelerator, and when that foot is removed power reduces as normal. This is very useful, says Robert Tappin, for long 40, 50 or 60mph stretches. He adds that drivers on night runs like it because they can set the speed and not have to keep glancing down at the tachograph with its integral clock: "Time always seems to go slower when driving on long runs at night, and the speed-hold control means that one does not have to keep glancing down," he says.
When driving on the Continent, with its different speed restrictions the limiter really comes into its own. No more having to nervously glance at the speedo, or butterflies in the stomach when handing over tachograph charts.
A road demonstration of the limiter fitted in a Tappins Volvo BlOM with a Plaxtons 3500 body demonstrates that there really is no surging or hunting — to the passenger it just appears that the coach has, like an aircraft, reached maximum cruising speed.
The smooth way in which maximum speed is reached is apparent both at 70mph and at intermediate speeds selected by the driver when using the optional speed-hold switch. The limiter does not stop the driver from using the gears to advantage as the limiter works on speed, not revs.
A glance at the tachograph chart will show that with the speed limiter in operation, changes in speed are virtually imperceptible. And not having to continually look at the speedo or tachograph in a 40 or 50mph built-up area takes a little of the stress out of urban driving no more hurried glances in the rear mirror for police cars when one sees that the speedometer has "suddenly" crept up to 55mph on a straight stretch of road in a built-up area.
REASSURING
During the test drive it was easy to accelerate out of the intermediate speed control, just by switching it off. Immediately the engine pushed the coach ahead faster. Another reassuring feature was that, unlike a cruise control, coach speed decreased as soon as the throttle pedal was lifted, so drivers need have no worries about accidentally taking corners on two wheels.
"Your average speed becomes your maximum speed — with the limiter in operation, you maintain a greater average speed," says Paul Tappin.
Reliability of the limiter is claimed to be excellent. Lucas Kienzle offers a 12month/100,000km warranty (which ever is the sooner). The actuator is sealed and is therefore maintenance-free. Because the actuator is mounted in an inconspicuous place, there is little chance that routine maintenance can damage it. The speed control module is mounted under the dash.
The driver himself is unlikely to be able to tamper with the limiter, and if it is interfered with, this will of course show up on the tachograph chart.
In the unlikely event of limiter failure, this will, again, show up either on the tachograph chart or as a fluctuation in speed of the coach.
The law on speed limiters appears to have been rushed through Parliament with little thought for the expense that coach operators are facing — or to the effect on motorway driving conditions. What will a speeding car do when it comes up on a coach in the outside lane of the motorway, doing a steady 70 and not easily able to move into the nearside lane? The driver will be sorely tempted to overtake the coach on the inside, bringing with it the risk of two prosecutions — overtaking on the inside and speeding.
Over the next two years, there will be a steady queue of coaches at Tappins where the staff will do their best to get the jobs done within the customers' timescales. Their advice is, don't leave it till the last moment.
EJ by Tony Pattison