A study was conducted to determine the effect on driver behavior of supplemental interchange signing on rural freeways, including various combinations of tourist-oriented attraction and service signs. Thirty-six test subjects" drove" the FHWA driving simulator over a 40-mi freeway course with 14 interchanges. Subjects were requested to scan the signs presented on an interchange approach and to exit the freeway if they saw a sign for the attraction or service they were seeking. Data were collected on the speed, acceleration pattern, and lateral placement pattern of the simulated vehicles on interchange approaches and on the distances from the signs at which the subjects recognized the logo or legend they were seeking. Supplemental signing in addition to that already permitted on a rural freeway interchange approach was generally detrimental to driver control behavior. Field tests should be conducted to confirm the behavior effects. The design of the supplemental attraction signs used in the simulation may have contributed to the changes in driver behavior, so designs that include different color schemes or that have picture logos as well as legends may be worth testing. Driver age, driver sex, and the number of supplemental service signs were other variables controlled in the experiment that were associated with control behavior differences and should be included in any future testing.