I am concerned that the design of the 'smart key' system is such that it would be possible to inadvertently leave the car running after parking the car in a home garage, thereby allowing dangerous carbon monoxide to accumulate in the home. This might happen because of two design features of the car: 1) the smart key system allows the car engine to run, when the key is removed from the car. With traditional keys, removing the key turns off the engine. With a 'smart key, ' removing the key does not turn off the engine/hybrid system. The owner must remember to turn off the hybrid system. Usually, of course, the owner will remember to turn off the car, but it would be all too easy to forget. 2) due to the nature of the hybrid system, the hybrid motor system can be turned on, and not make any sound at all. However, after some minutes, when the owner has walked away from the car, the engine will turn on, to recharge the hybrid battery. This will produce carbon monoxide. It would be easy to design the system so it would automatically turn off the hybrid system if the car were left idling, or with the shift lever in park, for a period of time, perhaps an hour. I believe this would correct this problem. It could probably be implemented at little cost with a software update. I have read that some car manufacturers have done this, but Toyota has not. Thus, I believe this is a significant safety issue, which would be easy to correct. I believe a fix should be required for new cars, and that there should be a required software update available for existing cars.

- Carmel, IN, USA