With winter here, contractors for the Dunedin City Council are preparing to start gritting and spraying the city's roads to keep the city moving in its darkest days.
With the season's first frosts already having appeared, night patrols started this week as part of the council's usual winter road maintenance programme, council roading maintenance engineer Peter Standring says.
On nights it was forecast or apparent it was going to freeze or snow, contractors would patrol roads, checking driving conditions.
Reports would be posted on the council's website (www.dunedin.govt.nz/road-conditions) from 6am each day and updated regularly through the day.
Mr Standring urged motorists to check the website before driving on the city's roads on mornings when it was frosty, icy or had snowed, and to consider whether their journey was necessary or could be made another way.
The onset of winter also meant the use of grit and anti-icing agent calcium magnesium acetate (CMA) was imminent, he said.
A map showing roads where grit and CMA were applied was available on the website.
More than 240 streets and roads were on the grit programme and about 15km of two-lane arterial roads were sprayed with CMA to prevent ice forming.
The roads on the gritting list were main arterial or collector roads, and were targeted so people had ways of getting down off the hills and around the city, Mr Standring said.
People on other roads had to find their own ways to get to the gritted roads, even if that meant walking to catch a bus.
He said it cost the council up to $140,000 a year for the grit and CMA on urban roads and up to $40,000 a year on rural roads, depending on how bad the season was.
The CMA cost about $3500 each time it was required, which included enough solution (about a tonne) to cover the 15km of two-lane roads given priority by the council and mixing and spraying the product on the road.
A CMA run was done about 10 to 12 times a year, depending on things like how long it would last. It could be effective for up to four days once spread, but also dissolved in rain.
The grit cost $1000 per eight-tonne truck-load for locally sourced material and included the cost of both the distribution and collection of the grit.
In the worst-case weather scenario, up to six trucks would dump 100 tonnes of grit a day on the city's roads.
Contractors had 96 hours to remove the grit, except for key intersections, where grit had to be removed by 5pm the day after it was laid.
Mr Standring said the council did not use salt for clearing ice or snow, but it was ideal for car parks and private driveways.
It could be used only in places where it would wash directly to stormwater systems that flushed out to sea, as it was detrimental to land and natural waterways.
If people wanted to know if they could use salt, they should contact the council for information about the stormwater drains in their area.
Council traffic engineers also issued a winter warning to motorists in the region about the importance of putting safety first when driving in unfavourable conditions.
It was time for motorists to modify their driving behaviour for winter conditions, senior traffic engineer Ron Minnema said.
Tips for getting around roads in winter
Driving
Defrost and keep windows clear of ice.
Drive cautiously and use headlights (low beam, if foggy).
Leave a longer stopping distance between you and other vehicles.
Be prepared to take a different route.
Use main roads treated with grit or CMA.
In snow:
Use tracks made by other cars, where possible.
Consider using public transport, or walking.
Cycling
Ensure lights are working and wear high-visibility clothing.
Give drivers plenty of warning of intention to change lanes or turn.
Use cycle lanes.
Walking
Use the right-hand side of the road/footpath (facing oncoming traffic) but on hilly streets, use the uphill side.
Wear high-visibility clothing.
Cross only at marked intersections.
If using headphones, keep volume down so you can hear traffic.
In frost:
The hardest frost tends to arrive at daybreak.
If possible, leave your trip until the sun is higher.
