The community response to the original article was overwhelming – we believe it was actually a new record for the amount of feedback Guardian News had ever received. Here is just a sample of what you had to say:

I commute from Macksville to Coffs Harbour on my motorcycle. Since the grinding I've noticed excessive wear on my tyres ie wearing unevenly. Prior to the grinding they were fine. My problem is the premature wear is an additional cost to me at around $600 for a set of tyres. I've spoken to a number of other motorcyclists who also are experiencing the same problem.

- Bill

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I travel from Nambucca Heads to Coffs Harbour every day. I, and other workmates, have definitely found after the grinding was completed there is drifting occurring.

- Brian

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I drive this section quite frequently as well as the sections further south. The grooves on the M1 down south are straight and do not pull my car around. You can see that the section between Macksville and Valla are not straight which is causing the vehicle to veer left and right all over the road. I also believe it will cause excessive tyre wear from pulling your vehicle from side to side.

- Dylan

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I have noticed a huge change when driving my vehicle on this road surface. I have a brand new vehicle and knew it wasn't the vehicle. I have even gone to the expense of getting new tyres, there's no change when driving on this ground road. I'm happy to take one of these "safety authorities" for a drive in my vehicle or even let them drive my vehicle to experience the UNSAFE road. The wet weather well the road is worse and their lit up sign that says 'road slippery when wet' should be enough to substantiate this. Come on RMS this is unsafe!!!! I also live at Valla and avoid this road as much as possible!!!

- Kathy

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I reluctantly drive the new highway by necessity. The new ridges between Nambucca Heads and Urunga make my car unsteady and I am so nervous I slow down to 70kph, I don't understand why you changed the road.

- Pauline

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I don't like driving over the new pavement grinding. My steering feels lighter ( I think that's how to explain it) I feel as though the car doesn't have enough traction and sliding. Hard to explain but definitely not right. I need to hold the steering quite tight.

- Rosie

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When driving on the new road I experienced my car swaying to stay on the road, as if I had a bulge or something in my tyre. I was also following a double tanker who was physically swaying in his lane.

- Kelly

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Hi I have also been affected by the veering of the car after the new grooves on the road were applied I also have found that one of the bridges heading north throws the car to the left when getting onto the bridge that goes over the Kalang River and has the little shack in the right hand side going north and am wondering if anyone else has experienced this. Thanks.

- Keily

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As per the story – vehicle veering quite dramatically. New 2016 car. Back seat passenger feels it greatly. Hard to hold to road, especially when wet.

- Deslie

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I have a late model (2016) 4WD Triton dual cab and I have definitely felt significant drift between BP and Ballard’s Rd exit on grooved parts of highway.  With the recent two weeks of wet weather, it has felt quite uncomfortable, as if I was about to lose traction at 100kph  I thought it was just me.  There was a recent single car accident (blue sedan) on that very stretch of road a week ago in a very straight section. Can’t help but think the road feel may have contributed, but that is just a guess.  I drive from Coffs to Newcastle and back every three weeks and this is the second worst part of the highway for road feel.  There are areas around Taree which are rough but that stretch is not virtually brand new like the Valla section.

- Michael

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It is the worst when wet . Extremely dangerous. Hard to keep your car on the road. Have witnessed several near crashes.

- Megan

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My car "walks" all over the lane! It feels even more unsafe in the wet. A friend of mine contacted someone at the RMS who admitted this kind of pavement grinding has not been tested at speeds over 75kph. We are doing 110kph on it! That friend I mentioned rides a bike. He had a brand new tyre on his bike three months ago. It had to be changed because it is now bald and he suspects the grinding is to blame.

- Mandi

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I noted your piece on the diamond grinding of the highway. Well might the RMS say the safety hasn't been affected because the first time I noticed it I was driving my little Combo Van returning from Coffs in some rather wet weather. When I got to this ground section of the road I thought the wind was blowing my van sideways until I noticed the wind wasn't too strong. It became obvious it was not the wind but the ruts in the road. By this stage I had slowed to 90kph but that didn't make it any better. The combination of the ruts picking up the wheels & moving them slightly with the effect of hydroplaning from the added water on the road made it a white knuckle ride to keep the vehicle within the lane markings till I got to the Nambucca Heads off ramp. I just hope we don't get too many inexperienced drivers getting into trouble because they may not realise what is happening & the correct action to take to keep safe. They don't teach young drivers how to deal with unexpected road surfaces and lack of traction like they used to when many roads were dirt and cross-ply tyres ruled the roads.

- Stuart

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Questions we posed to RMS:

1. How was the pavement tested after the grinding had occurred? There were a few people who said they believed the testing had occurred under speeds of 70kph or less. 

2. Did the testing consider safety of motorcyclists on the ground pavement? There were quite a few concerns raised by motorcyclists who felt they could no longer use the new highway because the ruts caused them to wobble uncontrollably, and wore down their wheels. They also said that in the wet the pavement is now worse for them than it was before the grinding occurred.

3. Did the testing consider the safety of caravans/ trailers being towed? We received quite a few responses from people who said they feel unsafe driving along the new highway with trailer in tow because they now struggle to keep it under control.

4. How did you come to the conclusion that the grinding was better for water runoff? One of the main concerns raised by local residents was that the new grinding exacerbated the effect of aquaplaning in the wet. 

5. Are there any further treatments planned for the pavement sections? If so, what are they?

And here’s their response:

Safety research on other sections of ground pavement in Australia and the US has not uncovered any adverse effects, and confirms the safety of grooved pavements in terms of vehicle performance and water dispersal.

Roads and Maritime Services is using the same techniques that have been used on the Hunter Expressway and other road surfaces in Australia and overseas.

Testing will continue. The pavement will be checked for irregularities that may adversely affect the ride quality of vehicles, noting that grinding is used as a technique to improve ride quality of concrete pavement surfaces.

If you are unsatisfied with this response, you can email our local Member, Melinda Pavey, who is also the minister that oversees RMS. Email oxley@parliament.nsw.gov.au or via this link.