Suppose you're driving north on Route 29 (Morehall Road), passing Uptown Worthington, and you want to head south on Route 202.

A sign posted on the overpass instructs you to turn right onto East Swedesford Road, but turning left will also get you to a Route 202 South entrance ramp. In fact, the ramp on the left is closer and drops you farther south on the highway.

So—why does the PennDOT sign recommend turning right, and driving past Penn State Great Valley?

We asked PennDOT spokeperson Gene Blaum, and here's the response we got:

I followed up by speaking to our Traffic Engineer.  The distance appears to be about 400 feet shorter if you make a left from PA 29 NB onto WB Swedesford Road to access the ramp to SB US 202.

The signs for SB US 202 South on NB Route 29 were originally installed in the 1990s because it is easier to accommodate larger volumes of traffic making a right turn than it is to make a left at an intersection, especially one with high traffic volumes like Route 29.

It is a rare situation where drivers have such a choice  like they do at Route 29 and Swedesford Road, but it would be somewhat confusing to motorists to have signs pointing in both directions for ramps along Swedesford Road.  Therefore, the right turn sign is used as it can handle the larger traffic volumes.

So, the right turn is better as a posted route for the bulk of traffic. But, if you're looking to save time during off-peak traffic, turning left onto West Swedesford Road might be a slightly quicker route to Route 202 South.