it may feel kind of creepy taking photographs of strangers from a car?
Some people are likely to think that you're police or MI5 doing surveillance. Or that you're planning a burglary, or intending to take pictures of children clandestinely. Or a million other reasons that people might dream up when they see a man with a camera in a car. You don't have to walk around a lot while doing street photography. Depending on where you live, there might be somewhere you can sit comfortably enough for a few hours, watching people coming and going, seeing what develops. And if your local area isn't good for that, a nearby big town or city is often ideal.
And if you sit (or stand) with your camera out where people can see it, you can satisfy their curiosity by politely answering any questions they might have. When people understand that you're a street photographer, they tend to leave you alone. I've only been challenged a couple of times since I started in 2007, and one of those was by a security guard in London's financial district.
When people have asked me how to get a start in street photography, I've told them not to worry about getting good shots to start with. Take photos that you like, not ones that you think other people will like. And challenge yourself at the start (and every now and then once you're comfortable with street photography) by picking a location and staying there, looking for ten shots to take home with you, not worrying about the quality. You'll start to develop good observation skills that way. Watch people's behaviour; notice how people often tend to do the same things over and over again; start to predict what people are going to do next, and have your camera ready.
Look at other people's street photos for ideas of what to look out for. A photo of a guy looking at his phone is OK, but a photo of the same guy with a street performing clown looking over his shoulder is much, much better. Go for unusual shots. Look through this thread and you'll see quite a few examples. Find your own style of shooting, and just as importantly, find your own style of post-processing, then people will start to notice your work.