In Pennsylvania the maximum freeway speed limit of 70 mph (113 km/h) is posted on select sections of rural freeway and most of the Pennsylvania Turnpike. The general speed limit on rural freeways is posted at 65 mph (105 km/h). The speed limit on urban freeways ranges from a low of 40 mph (64 km/h) in downtown Pittsburgh and Philadelphia to 65 mph (105 km/h) in some areas.
A total of 396 miles (637 km) of the Pennsylvania Turnpike are posted with a speed limit of 70 mph (113 km/h), including the extensions in Southwestern Pennsylvania. The speed limit of the Pennsylvania Turnpike is 55 mph (89 km/h) within construction zones and tunnels, at mainline toll plazas, and on the eastern approach of the Allegheny Mountain Tunnel and between Bensalem and the Delaware River Bridge. The speed limit is 70 mph (113 km/h) on 400 miles (640 km) of highway maintained by Pennsylvania Department of Transportation, including rural stretches of I-79, I-80, I-99, I-380, and US 15.
On non-freeway roads, speed limits are generally held at 55 mph (89 km/h) for rural four-lane roads, 55 mph (89 km/h) for rural two-lane roads, 45–55 mph (72–89 km/h) for urban four-lane roads and 40–45 mph (64–72 km/h), sometimes, but rarely, 50 mph (80 km/h), for urban two lane roads, 35–45 mph (56–72 km/h) for roads in commercial business areas, 30-35 mph (48-56 km/h) for major roads in residential areas, 20-25 mph (32-40 km/h) for most municipal residential streets, including main north–south and east–west roads in county seats and other mid-sized to large towns, and 15 mph (24 km/h) for school zones during school arrival and departure times only. It is also only in effect on days that the school the road goes near is in session. Many schools have signs that blink when the school speed limit is in effect. There is no reduced school speed on divided highways, even if the school sits right beside the highway.
All state-owned two-lane roads in rural areas within Pennsylvania have a default speed limit of 55 mph (89 km/h) unless otherwise posted.
The Pennsylvania Turnpike has a minimum speed limit of 15 mph (24 km/h) below the posted maximum speed, though the minimum is only sporadically posted. This is not enforced for slow-moving trucks in areas with steep grades and signs are posted that instruct drivers to use their flashers if traveling below 50 mph (80 km/h), 40 mph (64 km/h) if the speed limit is 55 mph (89 km/h). Pennsylvania has no default minimum speed limit on any other roads. However, minimum speed limits on certain highways may be enacted and posted as provided by Section 3364(c) of the Pennsylvania Motor Vehicle Code (Title 75 of the Pennsylvania Consolidated Statutes).
Drivers cannot be stopped by police for driving less than 6 mph (10 km/h) over the posted speed limit or 10 mph (16 km/h) if the speed limit is less than 55 mph (89 km/h) and non-radar timing devices are used, as use of radar devices is limited to “members of the Pennsylvania State Police”.