Speed limit on U.S. 40 decreasing from 55mph to 45mph PLAINFIELD, Ind. (WISH) — Drivers on U.S. 40 near Plainfield will need to ease up on the gas pedal. The Indiana Department of Transportation is reducing the speed limit from 55 mph to 45 mph, in an effort to improve safety along this busy stretch of highway. The speed limit change will apply to both directions of U.S. 40, spanning from just east of Ventura Boulevard to just west of Vandalia Boulevard and Mecklenburg Drive. INDOT says the new speed limit will go into effect on or after Wednesday. With safety in mind, INDOT is encouraging drivers to slow down, stay alert, and avoid distractions, particularly in and around work zones. All work schedules and plans depend on weather conditions, so changes could occur. View the WISHTV.com live traffic map Download the latest WISH-TV apps