It is the responsibility of the home owner to contact the city if a water valve cap is protruding the driveway. You should request a service technician to lower the pipe and cap to the level of the driveway. This service is free of charge. If the cap is not level with the driveway, it may very likely get hit and blown onto the lawn! Please make sure the city takes care of this situation before the first snow otherwise the city may charge you for repairs in the spring.