Gridlock/chaos/carnage
Since mid-April 2021, Cowley residents have contributed to a daily anecdotal traffic survey, in an attempt to track the initial change in traffic flow arising from the three Cowley LTNs. This is a non-scientific survey, there are no traffic counts, or queue-time measurement, however in lieu of systematic monitoring, there is a broad input from local residents via online platforms, local radio travel news reports, council roadwork notifications, Google Maps real-time traffic data, webcam time-lapse images, bus company service delay tweets etc. Taken together, these can form a reasonably accurate picture of the Cowley traffic situation on any given day.
The survey recorded any key factors contributing to traffic patterns on each day, and asked for anecdotal objective observations on the day’s traffic volumes and flow. After week 1 the survey started to reference the report from the same day in the previous week, in order to ask contributors to estimate if the traffic was much worse or better, slightly worse or better, or about the same each week. The anecdotal survey is planned to continue on a daily basis, and may be expanded to record traffic patterns in other parts of the city.
Key observations to-date are as follows:
- The traffic volumes on the Cowley perimeter roads have noticeably increased due to displacement from the LTNs. The ‘modal shift’ away from use of privately owned motor cars towards walking, cycling, public transport and car pooling is only just starting, meaning those vehicles that would normally flow through the three LTN areas are now contributing to the perimeter road traffic volumes. The same amount of cars using fewer roads leads to the increased traffic volumes on those roads
- There has been an initial increase in traffic volumes using one of the six of the LTN entry/exit roads, namely Westbury Crescent, as the same number of cars are using fewer roads to move about. A traffic reduction has been observed on the other five LTN entry/exit roads, where the road was previously a main cut-through route, namely Rymers Lane, Florence Park Road, Newman Road, Marsh Road and Temple Road
- The traffic volumes within each of the three LTNs has dropped significantly, as there is now no cut through traffic. This has shown that before LTN implementation there was a significant cut-through problem, which the LTNs have quickly addressed, i.e. before the LTNs a high proportion of traffic using the Cowley side roads was not made up of local residential traffic
- Since the LTNs were implemented, there have been a few days of gridlocked traffic (approximately 5-6 days in the 60-odd days since LTNs were first installed). On each of these days there has been significant contributory factors, namely the opening of non-essential retail after months of lockdown (caused 2 days of weekday gridlock), unannounced resurfacing (and closure) of all lanes of the eastern bypass (caused 2 days of weekend gridlock), and emergency gas repairs at the Marsh/Cowley Road junction, with a 3-way traffic light control in place (caused 1 day of weekday gridlock and 2-3 days of heavy congestion). This traffic pattern is no different to the pre-LTN situation, where there were a similar proportion of gridlocked days around Cowley due to similar contributing factors. Roadworks on Cowley’s main roads cause heavy traffic, which is made heavier due to LTNs removing the cut-through dissipation, but the LTNs themselves have not caused the heavy traffic in the first place
- Outside of these few days, Cowley traffic has not been gridlocked. Rush hour traffic has been generally heavier, but overall delays have been no more than 10-15 minutes driving through Cowley, the worst of which is at peak ‘rush hour’ periods on weekdays. Outside of these periods (middle of the day, evenings, weekends), there is light to moderate traffic flowing around Cowley
- Traffic levels in Oxford but outside of Cowley have steadily increased since lockdown lifting on 12 Apr. There is now regular heavy weekday congestion reported on other arterial roads, i.e. London Road, Botley Road, Iffley Road, Woodstock Road, Banbury Road. The increased Cowley traffic volumes are in-line with these city-wide increases. This supports the historical evidence that for the last decade at least, Cowley’s main roads have normally been congested at peak times, well before LTN implementation
- Bus usage remains well below average pre-pandemic levels at around 60%, although this is increasing week-on-week
- It is expected that the rush hour congestion will ease significantly out of term-time, when there is no school run traffic. The school run remains the primary opportunity for modal shift in and around Cowley
In conclusion….
- Traffic on perimeter roads is initially heavier due to the LTNs, with a trend to reduce slowly.
- All severe congestion (gridlock) observed to-date can be attributed to significant contributory factors – traffic displaced by LTNs has not by itself resulted in any gridlock.
- Modal shift takes more than a couple of months to gather momentum.
- The initial 6-month Cowley LTN trial will cover implementation delays, bedding-in, lockdown lifting, a number of local road improvements, up to 3 months of school (holiday) closures, and (hopefully!) the best weather of the year, all of which does not amount to a very indicative trial period.
Liveable Cowley supports a longer trial, ideally the full 18 months allowed within the Experimental Traffic Regulation Order (ETRO), due to complete in September 2022. This would provide meaningful assessment over different seasons, well outside of a pandemic lockdown scenario, and will also allow for sustained modal shift to take hold.
Further reading – https://wanderingdanny.com/oxford/2021/05/evaluating-ltns/
Glossary of terms used
Gridlock
Jammed traffic, unable to move freely between perimeter roads, due to the ‘receiving’ road already being ‘full’ with traffic. High occasions of very few cars flowing through traffic lights at each light cycle, due to jams. Generally over 15 minutes to pass through any one Cowley perimeter road
Heavy traffic
Queuing traffic, but able to pass through traffic lights onto the next perimeter road, moving with the lights. Waiting times of 5-10 mins to get through a set of traffic lights at peak times
Moderate traffic
Up to 5 min waiting time at junctions controlled by traffic lights
Rush Hour
Weekdays, from 08:00 to 09:00, and 15:30 to 17:00 (slightly earlier on a Friday).
Modal Shift/Evaporation
Changing from a usual mode of transport is known as modal shift. Changing away from private motor car to walking, cycling, public transport or car pooling is called evaporation, as it removes a private car from the traffic volumes.
Cowley Perimeter Roads
Oxford Road
Church Cowley Road
Hollow Way
Garsington Road
Rose Hill
Henley Avenue
Nearby Perimeter Roads
Iffley Road
Cowley Road
Barns Road
Donnington Bridge Road
The Slade
LTN Entry/Exit Roads
Westbury Crescent
Newman Road
Florence Park Road
Rymers Lane
Marsh Road
Temple Road
Note: The first planter in the three Cowley LTNs was installed on 8th March, but due to implementation and supply chain issues the LTNs were not finally completed until 22nd April, and technically the Florence Park and Church Cowley LTNs are still not complete due to the lack of ANPR enforcement at the Cornwallis Road and Bartholomew Road bus gates.