Auckland Transport (AT) recently conducted comprehensive bus trials in Connaught St, Blockhouse Bay to measure noise and vibration.
Local residents have become increasingly alarmed at the intrusion into their lives and the effect on their properties. Peter and Olwyn Over live 40 metres from a speed table. Their friend was visiting from Taupo and felt a shake while the crockery rattled. “We’ve just had an earthquake” said the alarmed visitor. Peter reassured them that it was just a bus going over a nearby speed table. They have also noticed damage appearing in their houses.
It is this sort of nuisance that got neighbours talking and eventually calling a meeting. Twenty people attended and at the meeting someone mentioned that there was also a group in lower Connaught St with identical concerns. The groups combined and approached the Whau Local Board who were then able to request that AT investigate the issue.
Simon Milner, AT Metro Services Team, led the trials. Three different size buses were used to test the speed tables at 30KPH and 40KPH. Four measurement points were set up on the footpath and inside volunteer neighbours’ homes. The in-home measurements were acoustic and vibration checks by contractor Marshall Day Acoustics. Meanwhile two staff rode on each test bus to determine the comfort level of the different driving approaches. AT had also previously used a speed counter to gauge the speed of traffic in the street overall. Identifying the problem is one thing. Fixing it is another. The buses are not even close to the 50KPH speed limit.
The move from smaller buses to medium sized 3 axled buses was when Peter Over first noticed the vibration problem from vehicles approaching uphill. A dry year may have also amplified the problem due to soil conditions. It appears that pressure waves are being generated by heavier vehicles as they impact on the front edge of the speed table. The effect is greater with increased speed and weight. When the trials were shared on social media, people from many different areas reported similar vibrations affecting their homes.
Trucks and light vehicles can also be very noisy as they go over the speed tables. Beacon asked Peter what he thought would be the ideal solution? “Remove the speed tables altogether” was his emphatic reply. This could be a warning for residents in other streets who want to stop speeding. It is a case of be careful what you wish for.