This article deals only with the magnetic fields of those hybrid cars can generate. It claims that those cars can generate "最高可达135毫高斯(磁场强度单位)". So the maximum field strength is about 135 milligauss. But you know the background magnetic strength of our earth is 0.5 gauss, about 500 milligauss. A small NIB magnetic bar the kids are playing is about 2000 gauss. You get the idea.
The magnetic field for an MRI scanner in a hospital is from 1.0 to 3.0 Tesla, and 1 Tesla = 10 000 gauss.
So I don't think the magnetic field generated by those cars is a major concern. But the high voltage is a concern for both the driver and the rescuers in case there is an accident.