The average cost of a gallon of regular gasoline in Texas reached $3.77 at the start of April, a 36.1 percent increase from a year ago, according to a SmartAsset analysis of AAA data. The national average is $4.06. Texas has the fifth-highest percentage increase in gas prices of any state over the past 12 months. Diesel prices have risen even more sharply, up 60.9 percent year over year....