塞 - Sai1 - Block, Clog, Stuff, Squeeze In

塞車 - Sai1 Che1 - Clog Car — Traffic Jam (in Taiwan!)

堵車 - Du3 Che1 - Stop Up Car — Traffic Jam (in China!)

This is one of those things that is said differently in China and Taiwan. I don’t think I know enough to characterize how different Mandarin as spoken in China and Taiwan is. I get the sense that they’re pretty different, maybe even as different as British English and American English.