keep the Hauliers have never been under greater pressure to
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minimise their impact on the environment. As part of this process, the Transport Road Laboratory is working on a guide to reduce CV noise pollution— including the noise created by truck bodies...
For the pedestrian standing at the roadside, there is a world of a difference between the noise produced by a passing tipper and that from a tanker. "Oil tankers tend to be pretty quiet because the tanks do not vibrate," says Geoff Day, manager of engineering policy at the Freight Transport Association. "They are rigid structures and most of them run on air suspension because the tanker fleets went down the quiet route quite some time ago."
He is one of up to 50 people among road transport industry associations and equipment manufacturers who have just received the first draft of a publication provisionally entitled Control of Commercial Vehicle Noise: A Guide to Best Practice.
By the end of June responses to this document will have been returned to the Transport Road Laboratory which is co-ordinating the project on behalf of the Department of Transport. "It goes through absolutely everything including body pivot points, panels, attachments, suspension...anything that can generate noise, and how it can be reduced," says Day.
Anything with flat panels that can vibrate, or where there is clearance between the body and the chassis, is a potential source of noise. On a tanker everything is bolted solid, but there are many places on a standard tipper that will vibrate and add to noise levels. Consequently, much of the focus is in the tipper sector, but the guide is designed to help the entire industry to build quieter vehicles— and to operate them more quietly.
The guide lists a number of priority areas: • Suspension systems; • Demountable containers and bodies; • Doors and fasteners; • Lifting gear; • Loose fittings.
Greg Harris, a senior researcher at TRL who is co-ordinating production of the guide, explains: "Unlike the powertrain these aspects are not covered by legislation and clearly it would be difficult to draw up legislation about what degree of body rattle there should be. It is intended to raise the awareness of the problems, but also to make suggestions about what might be done and to make vehicle operators aware about the steps they can take. For example, if a lorry driver was aware that a particular section of road was likely to cause a significant amount of additional noise at speed, he might slow down." Harris says much of the research follows from the success of steps taken by a tipper operator in the North of England in response to concerns voiced by local residents. These remedies included: • Rubber pads fitted under the tipper body to stop movement between the chassis rails and reduce metal-to-metal contact; • A self-clamping device to restrain body movement—available off the shelf from Hyva; • Rubber seals fitted to the tail gates—again to reduce metal-to-metal contact; • A switch to air suspension.
Apart from the change to air suspension, the remedies were achieved for low investment at the body building stage, and the noise reduction was significant.
Harris points out that no legislation covers noise generated on the road, so complainants have nobody to complain to. "If you happen to live close to a supermarket or retail outlet, it can be attributable to an industrial noise problem and the operators can be forced by law to take action," he says. Such is the consumer sensitivity involved in these cases that solutions are often found and arrived at quickly.
For example, Wincanton Logistics teamed up with Reliance-Mercury Vehicles last year to pioneer "the most environmentally friendly shunter in the world" for it's Warmley distribution centre in Bristol, which is operated on behalf of J Sainsbury. The shunter is liquid gas-powered, and hitching up to trailers has been made quieter by the installation of a modified Davies Magnet fifth wheel.
Back in February, delegates at the FTA's conference heard from Peter Stoakley, an executive in physical distribution at Marks & Spencer. M&S contracts out all of its transport but tries to be a good neighbour, making concessions on delivery times and routes to minimise inconvenience to its neighbours.
Stoakley told delegates of an incident at the Kings Road store in London. "We had all the quiet kit on our lorries, including gas refrigeration units, but this was not enough for the local residents," he said. They complained to the local authority and M&S had to respond, or face the possibility of losing permission to continue with night-time deliveries.
An action group was formed within the company and the situation was used as a testbed. "The drivers were briefed, modified load restraints were installed, we fitted sound deadening curtains to the trailers and fitted sound deadening shrouds to the rear of the store," says a spokesman. "We had introduced Euro-2 tractive units, and subsequently moved to gas powered vehicles. We also fitted door switches which turn off the radio as soon as the tractor door is opened."
M&S now has two compressed natural gaspowered vehicles and 10 liquified natural gaspowered vehicles on the fleet operated by BOC Distribution Services. It plans to convert more of the fleet to gas power, and is evaluating city diesel and low-sulphur diesel.
The good news, from an environmental point of view, is that cutting diesel exhaust emissions has also reduced noise. A spokesman for Perkins Engines explains: "When carrying out our engine work to advance our engines from Euro-1 to Euro-2 requirements, one of the primary things we were looking at was the reduction in NOX emissions. We found that a softer combustion was required. It resulted in a drop in decibel levels, somewhere in the region of 1.5-1.9 decibels at full load.
"To put that into context," he adds, "10 decibels is considered to be the level at which the human ear will perceive a noticeable reduction in engine noise."
The situation at M&S's Kings Road branch was resolved to the residents' satisfaction, not simply by changing the equipment used, but by changing the delivery procedures. Such procedural changes are also dealt with in the proposed guide, as is the role of the road surface in the generation of automotive noise.
As any pedestrian at the roadside would confirm, it's the humps and bumps in the road which makes vehicle bodies rattle. The tyre manufacturers have done a lot to make their products quieter (as well as making them safer and longer lasting). But, as Continental Tyre Group's customer services manager Roger Saunders points out: "The improvement gained from new road surfaces is potentially three times greater than the potential from tyre development."
The guide is designed to raise awareness about unnecessary noise generation among vehicle builders and vehicle operators. But the DOT should not attempt to lay responsibility for CV noise entirely on the shoulders of manufacturers and operators. It must remember that bad roads create noise, and adjust its road maintenance budget accordingly.
[:1 by Steve McQueen The report, Control of Commercial Vehicle Noise: A Guide to Best Practice, is due to be published by the end of the year Truck noise control: the London lorry ban The London Boroughs' Transport Scheme was established to maintain and enforce the London-wide weekend and night-time lorry ban after the abolition of the Greater London Council. The LBTS has recently been merged with the Transport Committee for London. it is now known as the Traffic Enforcement Unit.
The scheme is designed to prevent trucks over 16.5 tonnes from travelling on restricted roads unless they have legitimate business requiring them to travel there. It also ensures that trucks which do travel on these roads cause as little disturbance as possible. All permit applications are considered against a number of criteria, including "any special efforts made to ameliorate the environmental impact of the., vehicle". For example, airbrake silencers must be fitted.
The scheme also requires that: • The applicant and the driver of the vehicle must maximise the use of the M25 or other suitable roads outside the permit area as an alternative to using roads in the permit area; • The applicant should "eliminate avoidable noise, and reduce avoidable environmental intrusion". The applicant should also "so far as is practicable, ensure that all loads and equipment carried in or on the vehicle are firmlysecured (and if necessary padded) and the vehicle parts and equipment including chains, tailgates and doors are maintained in good order and properly used".
The requirements further state that every practical effort shall be made to minimise the noise of refrigeration equipment, particularly when the vehicle is parked. For example, half-power switching must be used as much as possible. Driver training and fleet management techniques, which can help achieve significant environmental improvements, should also be used.