This document describes a smart helmet system that uses sensors to detect if a rider is wearing a helmet and their blood alcohol content to prevent drunken driving. The system includes an alcohol sensor and helmet switch fitted in the helmet that send signals to a microcontroller. If both conditions of wearing a helmet and low blood alcohol are met, the microcontroller allows the vehicle engine to start. Otherwise, a GSM message is sent to alert authorities of potential drunken driving. The goal is to reduce accidents from not wearing helmets and driving under the influence of alcohol.