Yes, they can do this. An employer can make essentially any rules for employment that it likes, and this includes designating where employees must park. The fact that you do not feel comfortable or safe parking there does not, unfortunately, matter--the employer can still require that you do this. If you do not, you may be disciplined, up to and including being terminated, unless you have a written contract protecting your job (without a contract, you are an "employee at will" and have essentially no job protection).