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.
Where the speed limit is higher than 50 km/h, drivers continue to be required to reduce speed to a maximum of 50 km/h when children are present. Child safety is the primary reason for reducing speed limits in some school areas.