Traffic, syempre. Baka sa tolls palang or pagpasok palang ng SLEX ay magkaron na ng build-up kasi uwian yan.
Pero you can advice them not to take the Calamba exit, else.. sa Sto. Tomas exit nalang sila. At least may mabypass sila kahit konting portion nung provincial highway.
I went there couple of times this month, maluwag naman. Although my trips were early in the morning and late in the evening. One time pauwi ako hapon, traffic na nga.