While making a left turn at low speed, I applied the brakes, but the vehicle did not respond as expected and instead appeared to drift, surge, or accelerate forward. The vehicle struck a fire hydrant and a bus stop pole before crashing into a tree. Airbags deployed and both occupants sustained injuries. I suspect a possible malfunction involving braking, propulsion, electrical, or speed control systems. No final cause has been determined. The vehicle should still be available for inspection. Mercedes-Benz USA has opened a case regarding this incident.