Yes, TURNPIKE is a Scrabble word!

Letter values in Scrabble US: T 1, U 1, R 1, N 1, P 3, I 1, K 5, E 1.

Is it a valid word?

TURNPIKE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(from 16th to 19th centuries) gates set across a road to prevent passage until a toll had been paid
an expressway on which tolls are collected

Also: toll road.