If you exempt too many vehicles, congestion increases. Why should any be exempt?

The Mayor of London, Boris Johnson, has proposed changing the congestion charge exemption to include cars with conventional engines that emit low levels of CO2, in many cases lower than the hybrid or alternate fuel vehicles currently benefiting from taxpayer largess.

Under the current rules, the Alternative Fuel Discount gives drivers of alternative fuel and hybrid cars a 100% discount in London’s £8 Congestion Charge. (See London Congestion Policy Excludes Clean Cars?)

Under the Mayor’s new “Greener Vehicle Discount” proposal, any car registered after 1 January 2011 that emit less than 100g/km of CO2 and meet the Euro V standard for air quality will be exempt.

In addition, and as a way of encouraging more electric cars, the same exemption will apply to full battery electric and plug-in hybrid cars.

Volvo had questioned what place an emissions discount had in a congestion charge at all, not without self interest of course.  Then, Volvo lobbied that when a discount exists, there should fairness so that it did not bias one particular technology over another.

Volvo already offers a sub-100g/km Volvo C30 Sports Coupe. It has also shown a V70 wagon with plug-in hybrid technology that emits less than 50g/km CO2 – this technology will be launched in 2012 – and prototype versions of a full battery-electric C30.

(more…)