I am working on a design for a sump pump discharge for the basement of a church located in southeast Pennsylvania. The pump discharge is 1 1/2" PVC. I need run the pipe a total of 175 feet to a curb side gutter. The existing grade is approximately 2% . The pipe will cross under a public alley (15 feet macadam) and through the gravel parking lot of the church (160 feet).
Ideally, the section through the gravel parking lot should be perforated to reduce the amount of water reaching the curb. Due to existing  outlet, grade and curb limitations, I can only provide a little over 6" of cover. My concerns are :

1. Crushing of the pipe under traffic.

2. Freezing of the water in the pipe.

Can anyone provide me with technical assistance and product recomendations for this application ?