TPM of UK Roads

Why do TPM principles need applying to UK Roads?

A vehicle travelling along a stretch of road, having speed restricted for safety to 30 MPH should be able to complete a mile in 2 minutes.  If we assume that the average hourly rate of drivers on this route is £6.00 per hour, then every mile would cost the UK 20p for every vehicle.

It was stated that the cost of 20p is the cost to the UK, since it can be argued that indirectly all transport costs will affect the wealth of a country. At this stage the fuel cost is ignored, since the calculations would vary greatly depending on the vehicle, suffice to say that statistics from most sources show that a consistent speed over a given distance results in the best fuel economy.

If we drill down further and use an example of bread being delivered to a place in a town or city, then this can further illustrate the point. Our van carries 2000 items, therefore every mile travelled would result in 20/2000 or 0.01p per unit (neglecting fuel costs). If we assume a 3 mile journey then the cost per unit becomes not 0.03p but 0.06p since the van needs to return, although empty this time.

If we now consider the cost per minute of a delay in the route of the van carrying the bread. The drivers rate is £6.00, as stated above, thus the cost for every minute is 600/60 or 10p. Therefore the increase in cost of each unit in the van is 10/2000 or 0.005p for every minute delayed. The cost of the delay is eventually passed onto the consumer and thus affects their buying power. The consumer requires more income in order pay for the delays and thus needs a higher rate of pay. A higher rate of pay will increase the cost of products and services and thus determine how many of the products and services are sold to other countries outside the UK.

So just how can TPM principles be applied to UK roads

If there are no other vehicles are on a road, then theoretically a given vehicle should be able to travel at an average speed limited only by the legal speed limit on that road.

So what then can reduce this theoretical average speed neglecting other vehicles for the moment?

• Turning into or out of junctions - Vehicles need to slow down or stop

• Traffic lights - Vehicles maybe stopped.

• Roundabouts - Vehicles need to slow down to view and then negotiate

• Road Condition - Holes in roads etc.

• Road works - These generally slow down vehicles (traffic lights are mentioned above).

• Pedestrians - Zebra crossings or School patrols etc.

• Weather conditions - These can cause a speed reduction or else when severe can stop further travel.

• Road closure - Parades, accidents, emergencies etc.

• Miscellaneous - Things not mentioned above.

• Slower Vehicles - Tractors, JCBs etc.

• Built up areas. -

• Other Drivers. -

The nearest to the ideal we have in the UK is the middle stretch of a motorway, even the M25 when no other vehicles are on it.

In looking at TPM improvements, cost versus saving need to be considered. From the list above, traffic lights could arguably be the one that could be improved with the lowest cost. How many times have you approached a traffic light only for this to turn red just because of the timing. Perhaps you have approached a Red traffic light but had to slow down until the lights change to Green, this is still a delay. How easy would it be to have a proximity sensor at some distance away from a traffic light that would initiate a change to Green allowing the approaching vehicle to maintain it's speed.

So what is wrong with the operation of modern day traffic lights and how can they be improved?

When approaching a traffic light that is RED and in the absence of other vehicles then the lights should change to GREEN allowing the vehicle to maintain the legal speed. Where there is a number of traffic lights on a main road

You can contact me at martin@martinlee.co.uk
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