> The National Maximum Speed Limit (NMSL) was a provision of the federal government of the United States 1974 Emergency Highway Energy Conservation Act that effectively prohibited speed limits higher than 55 miles per hour (89 km/h). It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis and remained the law until 1995.

I've always been under the impression 55 was the optimum speed for (ICE) fuel efficiency.

Does this change at all for electrics (given regenerative braking)?