For the better part of a year, at the least, Navistar has challenged the EPA’s emissions regulations that allow heavy- and medium-duty bus and truck operators to go the route of selective catalyst reduction to meet more stringent emissions requirements for 2010. The impasse has apparently been resolved, for now.
Greenwire by Environment & Energy Publishing reported this week on its Web site and in the New York Times that the vehicle manufacturer, which owns IC Bus and selected exhaust gas recirculation, or EGR, as its 2010 emissions solution, agreed to drop three lawsuits this week tied to assertions that the EPA failed to take into account that operators could potentially drive their buses and trucks without the urea, or diesel exhaust fluid (DEF), that makes the SCR-equipped vehicles compliant with federal clean air rules. Earlier this summer, a study commissioned by Navistar found that operators could run their vehicles on empty DEF tanks or by filling them with water instead for up to 13,000 miles.
A California Air Resources Board representative told us in July following a joint workshop with EPA that the current federal rules account for this possibility because SCR has reserve DEF that kicks in if a bus or truck runs low or complete out of the additive. In the July School Transportation News magazine special report, a school bus dealer in Wisconsin said that, in today’s age of preventative, predictive maintenance schedules, it was unrealistic that operators would allow their DEF tanks to run low in the first place, calling such an irresponsible practice akin to allowing the vehicle to run out of fuel.
Still, Navistar asserted that it was a possibility that SCR operators might skirt the rules, or at least they were able to do so. This prompted a strongly worded response last week from Daimler Trucks North America, which owns Thomas Built Buses, stating “Enough is enough,” alleging even that Navistar paid a truck operator to “break the law” by running the SCR-equipped truck mentioned in the study out of compliance.
Congress even got involved two weeks ago as several House Democrats signed a letter addressed to EPA Administrator Lisa Jackson and CARB Chair Mary Nichols voicing concern over SCR and an apparent “relaxation of EPA’s NOx emission standard.”
Now, with the lawsuits behind them, EPA and CARB are expected to move forward with re-examining how buses and trucks are certified, as was decided at last month’s emissions workshop.