If a section of SH5 is lowered to a speed limit of 80 km / h, the additional travel time will be between 4 and 11 minutes, the NZTA recalculated after initially saying it would be less than one minute. Photo / Warren Buckland
Waka Kotahi now claims that the average increase in travel time if an 83 km section of Napier-Taupō Road was lowered to 80 km / h would be between four and 11 minutes.
In April, when Waka Kotahi NZ Transport Agency submitted the proposal for public consultation, it initially said the average increase in travel time would be less than one minute.
In a talking point published in Hawke’s Bay Today on April 24, Waka Kotahi’s regional relations director Emma Speight wrote:
“Our technical evaluation of the road revealed that although the posted speed limit on SH5 between Rangitaiki and Esk Valley is 100 km / h, the average speed at which people are traveling is 81 km / h. lowering the speed to 80 km / h will increase the average journey time by less than a minute. “
On May 26, in a project update posted on his website, Waka Kotahi said he believed “people will experience a four to 11-minute increase in travel time on State Highway 5.”
Two methods were used for the recalculation.
Method 1 calculated the time difference between the current average passenger speed and the proposed speed limit.
“This method assumes that where people are currently traveling over 80 km / h, they will now drive 80 km / h and where they are traveling below 80 km / h, their speed will remain unchanged.
“The data we used when we first launched the consultation collected data over a two week period and divided it into four similar sections. Applying the first method to this data showed a very small increase of less than a minute. “
In recalculating the likely impact on travel times, the NZTA used a different data source, a longer period of three months, and divided the length of the corridor into smaller 2 km segments that “better reflect the length of the corridor. different typography of the road “.
“For this reason, we expected some variation in the result.
“Our additional analysis has a different result.
“The more detailed data suggests that the increase in travel time northbound will likely be around 3.5 minutes and 4 minutes southbound.
Method 2 calculated the time difference between the posted speed limit and the proposed speed limit.
“Based on the second methodology, the increase between the posted speed limit of 100 km / h and the proposed speed limit of 80 km / h, the increase would be just over 11 minutes for the entire proposed length of 76 km.
“This method works assuming people are driving at the posted (and proposed) speed limit along the entire length, including very windy parts, of SH5.”
The consultation ends at 11 p.m. on Sunday.