The IM240 test is a chassis dynamometer schedule used for emission testing of in-use light duty vehicles in inspection & maintenance programs implemented in a number of states.
It is a short, 240 second test representing a 1.96 mile (3.1 km) route with an average speed of 29.4 mile/h (47.3 km/h) and a maximum speed of 56.7 mile/h (91.2 km/h).
Figure 1. Inspection & Maintenance Driving Cycle IM240