Every time I have to stop a car on our traffic light system, I feel guilty.
Why are you doing that? Is stopping cars part of your job?
Yes, I work with my brother to stop cars.
You shouldn't feel guilty over something so trivial especially when it is your job. You are controlling traffic by doing your job.
I still feel guilty even though it's my job and not paying attention to traffic lights is dangerous.
I think he would feel more guilty if he didn't stop them and they caused an accident. You should feel justified in doing your job, and it should feel good to know that you are preventing someone from doing something dangerous that could hurt people.