Speedway Smog Center has been the leading "test only" smog provider in Modesto for the last 18 years. We have fast and reliable service 6 days a week. Our technicians bring over 50 years of experience to meet all your smog inspection needs. The benefit of using a "test only" smog center is you will have the peace of mind knowing, we are here to smog your vehicle without trying to sale you more vehicle related services or repairs.