Can One Open a Car Door on Shabbat?

Quiz

1 - What biblical prohibition could potentially be violated just by opening a car door on Shabbat?

• Turning on incandescent lights in the car.
• Lifting muktzah objects.
• Tying permanent knots.

2 - What rabbinic prohibitions could potentially be violated by opening a car door on Shabbat?

• Allowing objects stuck inside the car to leave the t'chum Shabbat.
• Activating electronic systems and marat ayin.
• Missing the proper time to pray Musaf on Shabbat.

3 - When would it be permissible to open a car door on Shabbat?

• When one needs to remove his father's siddur or tallit from the car so that he can pray.
• When it is already within 3 hours before the end of Shabbat.
• When the car door is completely disconnected from a car's electronics and the car serves as a form of shelter.