Over the past century, countless people have died in traffic accidents, especially caused by drunk driver.  Lots of family were broken by those irresponsible drivers. In order to under control those traffic accidents, Hong Kong Government sets up series anti-drink driver laws to protect the road safety. When a cop stops your car, he can tell by just flashing a special torch at you whether you are drunk or sober. That’s because it has an alcohol detector. To ensure the road safety, Sweden, Australia and some states in America have enacted laws requiring drivers who have been caught drunk-driving to install an alcohol ignition interlock device in their cars. The driver must blow on it before starting their cars. If alcohol is detected, the car won't start. So will engineering be more effective to prevent the traffic accidents?