Have you considered using the road from the Chain Hills tunnel through Abbotsford,Neil St., Boomer St.,through the old cement works and follow the old railway past the old freezing works and onto the kaikorai valley cycleway thereby bypassing the dangerous Burnside corner.
An excellent idea. Use prisoners as labour to repair the surface and fit necessary ventilation and lighting.
@Phil: 2nd tunnel is Chain Hills tunnel to complete an 8.5km track from Caversham to Wingatui. A large portion of the $3M is roadworks in Fairfield to widen a rural road to paint cycle lanes onto it!!
fantastic Idea
What is the second tunnel, Annabelle?