galston road allows direct access between galston and hornsby heights, and is the only road that extends through the entirety of galston gorge. via the gorge, travelling from galston to hornsby heights takes approximately 20 to 25 minutes. alternatively, detouring around the gorge via boundary road takes approximately 40 to 45 minutes, and can increase significantly during peak hour times. from tunks creek bridge to hornsby heights, the narrow road stretches approximately three kilometres with an average incline of 5%, and contains six tight hairpin corners. of the five initial hairpin turns, the most gentle are the first and last, while the three in between are notoriously steep. light vehicles or vehicle combinations greater than 11 m in length are unlikely to successfully navigate the road conditions, and heavy vehicles over 7.5 m in length are prohibited. the road contains a guard rail along the berowra creek side of the road to enhance its safety.