The £2.9 million Phase Two is part of the joint Masterplan scheme by Buckinghamshire County and Wycombe District Councils, and the Local Enterprise Partnership, to give traffic another way through the town centre from Oxford Road to Marlow Hill.
The scheme will use similar designs to Phase One, which opened in December, creating the new Oxford Road/Westbourne Street junction and featuring narrower traffic lanes, wider pavements, tree planting, and low-profile central strips.
Phase Two along Desborough Road aims to keep traffic flowing in a slow and steady way without the need for traffic lights or conventional roundabouts, and with fewer signs and white lines.
At the start of works, the junction of West End Road and Desborough Road will close permanently to vehicles in preparation for future work to create a new Bridge Street junction. This answers concerns about the safety of cars turning there. Access to the car park near the junction will be via West End Street.
Traffic lights at the junction will be replaced by temporary signals, and a new pavement created across the mouth of West End Road.
Contractors will then start work outside Guildmaster Court to widen the pavement and create six new parking bays. Work between Desborough Road and Bridge Street junction, and on the remainder of Westbourne Street, should be completed by Christmas.
Work between Bridge Street junction and Lily’s Walk will continue in the new year.
Once Phase Two is finished in August 2017, work will begin on the final phases of the alternative route, including a new link road through the gas works site to Suffield Road, and improvements along Queen Alexandra Road to the Abbey Way gyratory.
Mark Shaw, Buckinghamshire County Council's Transport Cabinet Member said: 'We listened to feedback from residents and businesses during the consultation in July, and the suggestions have helped us further shape the design. I fully appreciate there will be some inconvenience while work goes on, and I apologise in advance, but I believe the resulting gain will be well worth the pain!'
David Johncock, Wycombe's Cabinet Member for Planning and Sustainability, said: 'The alternative route is a "big picture" project for High Wycombe with significant investment for the town. It’s ambitious and will take time to complete. As well as making improvements to the street scene, and creating a new through route, the alternative route will pave the way for other regeneration work in and around the town. Whilst the necessary roadworks to create the central element of the route will take some months to complete, we are working closely with BCC to keep Desborough moving.'