After 8 to 12 days, on average, symptoms of measles can begin. The period between measles transmission and the start of symptoms is called the incubation period.
Driving Laws In Greater Philadelphia. The maximum speed limit in Pennsylvania is 55 miles per hour unless posted otherwise. The maximum speed limit on interstate highways is posted after each interchange; on other highways the maximum speed limit is posted at approximately half-mile intervals.
When driving within 500 to 1,000 feet of a school while children are outside or crossing the street, the speed limit is 25 mph unless otherwise posted. Also, if the school grounds have no fence and children are outside, never drive faster than 25 mph. Some school zones may have speed limits as low as 15 mph.