Should the driver pay half the blood money (Diyya) and is atonement (Kaffara) incumbent upon him if specialists determine that he bears half the responsibility in a traffic accident that resulted in a person's death?

The responsibility for a traffic accident is not divided between the killer and the killed. If the driver took all safety precautions and did not cause the accident, then there is nothing upon him. But if he was negligent in any of these matters, then he is responsible and obligated to pay expiation and blood money. This detail is between him and his Lord.