This comes as union members are conducting a nationwide strike authorization vote.
The results will be announced on Friday.
A strike could be devastating for both the company and the overall economy.
Air conditioning in trucks was a major issue in the discussions. Union members say temperatures can exceed 120 degrees in the cargo areas of those trucks.
Last year, a 24-year-old UPS driver from Downey died on a hot summer day while delivering packages in Pasadena.
UPS driver, 24, collapses and dies while delivering packages in SoCal heat
24-year-old UPS driver dies while on route in Pasadena, possibly due to heat stroke