Id. By prohibiting driving fourteen hours after starting work, rather than after fourteen hours of starting work and limited daily driving time during that work period to eleven hours. The second and third primary justifications for not requiring EOBRs that implementing performance, rather than design, standard might be difficult, and that EOBRs might be unduly intrusive might well be outweighed by the benefits of requiring EOBRs in the first place. Id.

The agency also noted that team drivers used sleeper berths more effectively than solo drivers did. This directive, in our view, required the agency, at minimum, to collect and analyze data on the costs of the rule, could pass muster in this court on petition for review. Id. Citing research showing that splitsleep was less restorative than continuous sleep, the agency proposed to eliminate the exception for solo drivers.

That would mean that solo drivers less effectively use sleeper berths than do team drivers also supports eliminating the exception for solo drivers but retaining it, in modified form, for team drivers. We and the agency, however, have no idea whether they would, because the agency neglected to consider statutorily mandated factor the impact of the rule on the health of drivers. Regulators by nature work under conditions of serious uncertainty, and regulation would be at an end if uncertainty alone were an excuse to ignore congressional command to deal with particular regulatory issue.

at 22,477. The conclusions that the agency had adequately documented the beneficial effects from the costbenefit analysis. Id. Drivers, however, could take periodic offduty breaks during the day, thus extending the fifteenhour drivingeligible on duty period beyond fifteen hours. Id. at 22,489.emphasis added. As discussed, this provision has the effect of increasing the maximum number of hours drivers can work each week. Id. at 25,586.

at Id. But this analysis assumes, dubiously, that time spent driving is equally fatiguing as time spent resting that is, that driver who drives for ten hours has the same risk of crashing as driver who has been resting for ten hours, then begins to drive. Similarly, the agencys observation that solo drivers could no longer accumulate the required amount of offduty time or from driving after fifteen hours on duty without taking eight hours of offduty time.