money is not the thing being measured but the instrument with which we measure it


Vehicle Weight

This week Parkrun was in the headlines as a local council decided it should contribute to the upkeep of the paths it was held on.  The council cites £60,000 it has to spend in park path maintenance as the reasons behind the change in stance.
If councils want to save money on infrastructure, cracking down on people running around parks isn’t the first place they should start.
In the south west it is estimated it would cost £1.1 billion to get roads back into an acceptable condition. The UK as a whole spends over £4 billion on road infrastructure damage, more than three quarters of which is from the damage caused by passenger cars and HGVs (figure 1, taken from wattsthecost.info).

Roads are often perceived as the cheaper more flexible option, aside from their “carbon emissions”, but when it comes to the environment there is more than just exhaust emissions to consider. As discussed in wattsthecost’s previous blog, the majority of particulate matter emissions from road transport are from non-exhaust emissions, of which dust from road abrasion is a significant contributor.

When a road wears down, cracks up and can no longer be patched, it goes to landfill. Some reuse options are available, but like car tyres the product deteriorates after each cycle.

A few weeks ago it was reported that autonomous trucks will be trialled on the M6 as part of a drive to “cut traffic congestion”. This seemingly highly sophisticated technology is similar to a 19th century British Invention: the train.

But even in the 1800’s train/tram technology was far superior to these autonomous trucks. In 1885 Frank Sprague invented the regenerative electric motor, made famous with its introduction to Formula 1 more than 100 years later in 2009. Coupled with solid steel wheels on hard tracks, Sprague’s trams used comparatively tiny amounts of energy.

In addition to energy savings, Kintetic energy recovery (KER) using electric motors means we don’t have to use friction to brake at all, eliminating the dust and metal waste produced by disc brakes. Trains and trams run on solid steel wheels, producing a fraction of the dust of a soft car/bus tyre and these wheels and tracks can be melted down and completely re-used once their life is over.

Despite the efficiency of vehicles improving by around 20% since 2005 a car still only converts around 17 – 21% of the energy in the oil into motion. Compared with an electric motor which can convert upwards of 90%.

The association of American rail roads estimates a train can, on average, move 1 ton of freight 479 miles on 1 gallon (4.54 litres) of fuel. Using trains cargos far heavier and of similar sizes to trucks regularly reaching over 2km, in some cases 6.5km in length can be transported with only one driver.  No autonomous technology is needed, although in recent decades modern electronics have made rail travel one of the safest methods we have for moving people and goods around. In the UK trucks, buses and coaches are responsible for 1 in 5 road deaths despite making up only 1 in 50 vehicles on the road.

Up until the second world war Bristol had a tram network that would rival any modern continental city. However the main supply cables were destroyed by a Luftwaffe bomb and like most UK cities it embraced the motorcar.

Despite the huge potential energy and air quality improvements coupled with the associated cost savings to the public, Bristol city council considers trams too expensive. Instead Metrobus, a dedicated route for a low efficiency combustion powered bus is perceived as the cheap option, simply because less upfront physical infrastructure has to be installed.

Britain is one of the few countries in Europe to have double decker buses in city centres. This is because we use them as our primary public transport mode, when other major cities use rail, and it is costing us a fortune.


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