Pittsburgh drivers will almost always slow down when going through a tunnel, even when there is no other traffic. Pittsburgh drivers are usually very courteous. They will often let you take your turn to merge into traffic, let you turn across traffic at an intersection. However, at on ramps, many drivers treat Yield Signs as STOP, so don't be surprised to find someone stopped at the end of the ramp. Call for pickup.
Taxis are generally available around the downtown hotels.
Cash, not CabCharge. Oakland is reasonably safe at night, but avoid the back streets parallel to Craig Street. Downtown is also reasonable safe, but there is little going on. It is not a measure of food or service quality. Many are closed on Sunday and some on Monday.