Lateral velocity and tire-road forces are vital signals that affect the stability of a vehicle under cornering. Unfortunately, for both technical and economic reasons, these fundamental vehicle parameters can hardly be measured directly through sensors. As a consequence, an efficient and reliable algorithm for estimating vehicle lateral velocity and tire-road forces is needed. This paper presents a novel framework for estimation of vehicle lateral velocity and lateral tire-road forces. The proposed algorithm is based on switched interval observers and is able to cope with changes of tire operating conditions. The interval estimation algorithm is evaluated through experimental data acquired using an instrumented vehicle. Simulation results show that the developed system can reliably estimate the upper and lower bounds of vehicle lateral variables during both steady and transient maneuvers.