Debate diesel before changing policy

Posted on June 30th, 2015 by Rob Marshall


Following GEM’s earlier blog on the political tide turning against diesel cars, it appears that Glass’s Guides, one of the UK’s foremost automotive valuers and data providers, shares my concerns about hasty government policies being adopted, without any in-depth debate.

Indeed, Glass’s agrees that knee-jerk responses to the alleged negative impact that diesel car emissions have on urban air quality might be counterproductive, not only in environmental terms but the wrong move will also prove costly for both consumers and businesses.

While I do not agree entirely with Glass’s Head of Valuations’ sweeping statement that the latest diesel engines are virtually as clean as petrol (the SMMT has issued a similar statement, possibly to encourage more sales of new cars, the makers of which constitute much of its membership), an additional comment that casts doubt upon hybrid petrol cars being cleaner than diesel is an interesting declaration that should be justified in more depth to the policymakers.

Apart from hinting that the current poor air quality in cities is in response to previous governments’ ill-advised policies, Glass’s added that raising taxes on current diesel vehicles is unlikely to have a positive effect on air pollution, because few owners would be able to justify the expense of switching their vehicle for one that runs on an alternative fuel.

Consider reliability and garage costs
From GEM’s technical perspective, modern diesel passenger cars are totally unsuited to consistent stop-start city conditions and we field regular complaints from low mileage users that experience reliability issues, when exposing their vehicles continually to those conditions. Therefore, drivers that cover a low mileage at consistently low speeds should discount diesel ownership, not necessarily for environmental reasons, but because modern diesel engines are at their least polluting and most efficient/reliable, when driven on long trips at higher speeds.

It seems that both businesses and private buyers are realising this, with Glass’s reporting that the latest new car sales figures are seeing both alternative fuelled vehicles and hybrids nibbling into diesel’s substantial market share. However, diesel vehicles (both old and new) tend to perform at the most efficient and environmentally-effective when out of the cityscape and, with this being realised, either banning them, or imposing punitive taxation, is likely to be the wrong political move.