I have been trying to get a response from Tesla about this issue since January 2015. I have called my service adviser many times and have written multiple times to ElonMuskOffice. The issue concerns a safety issue regarding the Model S regenerative braking system performance on ice. The Model S performance is extraordinary in most conditions. It even drives well in snow, with appropriate snow tires. The traction control system is excellent, and it is a good feature to be able to adjust the regenerative braking to “low” in snowy conditions. The trade-off of efficiency vs control of the vehicle is certainly worth it. However, in icy conditions the situation is very different. I was caught in an ice storm in New Hampshire on January 18th. I have to tell you that driving the car, even with the regenerative braking set to low, was terrifying. Any time that I lifted my foot even slightly from the accelerator pedal caused the rear end to twitch. There was nothing I could do to prevent it. Even at low the minimal braking application degraded the vehicle’s stability. That day the storm was supposed to be a rain storm but the air temperature was cold enough that it became an ice storm. I actually made it about 14 miles (in nearly an hour of driving) but just shy of Interstate 93, which I knew would be treated. I take full responsibility for the accident, because I could have (and should have) pulled over and waited out the storm. However, I believe that the regenerative braking system contributed to the accident. Based on what I have learned from experience, I would like to strongly urge Tesla Motors to add a third option to the regenerative braking setting of “Off”. They should not try to have their engineers come up with a software solution for detecting ice, because on ice once there is any wheel slippage it is already too late to regain control. Tesla should trust the intelligence of its customers and add the ability to disable the regenerative braking completely. That would make the car much safer on ice.