International ProStar

The result of five years and roughly $300 million in development, the ProStar (2006-2016) was built to deliver class-leading fuel efficiency for Class 8 on-highway work. Independent on-road testing confirmed it averaged 5.7% better fuel economy than the Freightliner Cascadia -- a margin Navistar pegged at nearly $4,000 a year (about 1,300 gallons) at 144,000 miles and $3 per gallon; the platform was later relaunched as the International LT.