This road was built for the construction of the new express railway to Dodoma and is closed for regular traffic as it passes inside the railway's security barrier. There are several guarded gates but cyclists are allowed through. So far it's in good condition (I'd say borderline for a regular touring bike, perfectly fine with 50mm+ tires) and save for the occasional railway serviceman on a motorbike you're all alone on the first part going west. The part going north to Kiluvya Hills is a public dirt road but you're still likely to meet more chickens than motorized vehicles.