Vehicles are on the way to enabling hands-off-the-wheel driving on freeways, with trials of automated vehicle technologies underway on one of Australia’s largest tollways.
EastLink’s 40km road network is the largest privately operated network in Victoria. EastLink is the major north-south transport artery in Melbourne’s east, connecting the Eastern, Monash, Frankston and Peninsula Link freeways. EastLink is Melbourne’s fastest road and safest freeway, with traffic averaging 250,000 vehicles per day.
Production vehicles with Level.2 automated vehicle technologies are already on Australian roads, at progressively lower price points, and with increasing numbers.
Level.2 means partial automation of steering, acceleration and braking. At least one of the driver’s hands must be on the steering wheel at all times.
One of the most widely implemented automated vehicle features in these cars is highway autopilot.
Today, highway autopilot generally means a combination of lane keeping assist (the vehicle steers itself within the lane) and adaptive cruise control (the vehicle adjusts speed via acceleration and braking to maintain a safe distance to other vehicles), with onboard sensors dynamically monitoring the presence of other vehicles and road users.
In freeway conditions, this supervised driving allows a more relaxed driver load when
used according to the vehicle manufacturer’s guidelines.
Some of the latest vehicles also include autonomous overtaking, which the driver initiates by flicking the indicator stalk. The vehicle finds a safe overtaking opportunity, autonomously implementing the overtaking manoeuvre with indicator signals.
Emergency auto-braking, already available, will be supplemented by automatic collision avoidance, involving a combination of steering and braking.
While vehicles are now reading speed limit signs to inform motorists and provide warnings when the speed limit is exceeded, the next innovation will be automatic adjustment of speed to the prevailing limit.
Over the next few years, technology step changes such as these will be combined together by vehicle manufacturers to enable Level.3 conditional automation, with all aspects of the driving task automated under certain circumstances (for example, hands-off-the-wheel driving on freeways).
The driver must be ready to take back control when prompted by the vehicle. This will of course be subject to legislative changes in each jurisdiction.
The Eastlink Trials
Some of the latest vehicles on sale today already have the necessary hardware sensors to take the vehicle from the current Level.2 highway autopilot all the way to Level.3 hands-off-the-wheel driving on freeways.
This will be achieved through software upgrades (at regular service intervals or by auto-download via wireless data networks) together with high definition maps for automated driving and sensor augmentation where necessary.
Therefore testing the compatibility of existing freeways such as EastLink with the latest Level.2 vehicles is a useful task to provide early warning of any incompatibility, so that it can be addressed by vehicle manufacturers and freeway operators.
This will expedite the development of Level.3 hands-off-the-wheel capability.
As the operator of a major freeway, EastLink needs to assess the envelope within which Level.3 hands-off-the-wheel capability will safely operate.
Which parts of EastLink, or the whole network? At what times, or all of the time? Under which conditions, or all conditions?
These are some of the practical purposes of the EastLink trials, making them the first of their kind in Australia.
The trials are being undertaken by EastLink in partnership with VicRoads, the Australian Road Research Board, La Trobe University and RACV.
While EastLink, which complies with VicRoads’ freeway standards, is the main test site, trials also include stretches of other VicRoads freeways.
Although the trials are being conducted for the benefit of EastLink and VicRoads, trial results will be disseminated nationally, and freeways across Australia may benefit from adjustments made by vehicle manufacturers as a result of the trials.
EastLink trials have already been conducted with vehicles provided by a range of manufacturers including BMW, Honda, Mazda, Mercedes, Mitsubishi and Volvo.
The most recent technology demonstration involved the new Tesla Model X. Additional manufacturers, including Audi and Toyota, will soon be providing vehicles to assist the program.
Key trial results so far
The trials have already identified opportunities to improve the compatibility between new technologies and freeway infrastructure. For example:
Line markings:
- Good quality of line markings – including reflectivity and luminosity – on both sides of the lane are essential to avoid “dropouts” of the lane keeping assist function, and to help a vehicle maintain its position centrally in a traffic lane. Partly driven by the trial results, EastLink has recently repainted 100 per cent of its line markings.
- Gaps in contiguous line markings should be avoided, as this may lead to dropouts of the lane keeping assist function or unintentional lateral movement.
- In construction zones, the use of temporary yellow line markings conflicting with white line markings is incompatible with the lane keeping assist function, causing dropouts. The automated functions in different vehicles may dropout with varying amounts of advance warning. When planning traffic management for construction zones, road operators will need to consider whether lane keeping assist dropouts are acceptable on a case by case basis.
Speed signs:
- Consistency of speed signage (format and placement) and maintaining line of sight visibility will enable more reliable interpretation by vehicles.
- Speed signs on freeway exit ramps or side roads need to be located well away from the main carriageway so they are not confused for main carriageway signs.
- Conflicting or confusing speed signs should be avoided, as vehicles find it very difficult to determine the correct speed limit under these circumstances. This could occur within a construction zone where there is poor implementation of traffic management plans, or in circumstances where different speeds apply to different vehicle types (e.g. a lower speed limit for trucks).
- Variable speed signs are increasingly deployed on Melbourne’s freeways. Roadside variable speed signs are read very well by some vehicles, while other vehicles are not yet reading them reliably.
- The flashing annulus feature on variable speed signs (when speed is lower than normal) is not expected by some vehicles, impacting recognition.
- In general, overhead speed signs, which are an increasingly common format on Melbourne’s freeways, are not yet read reliably by vehicles.
Lane control signs:
- Overhead lane control signs (lane open or closed) are increasingly common on Melbourne’s freeways. However, they are not yet recognised and used by vehicles.
Vehicle manufacturers and freeway operators are now able to work on taking advantage of these opportunities to further improve Level.2 performance, which will pave the way for the introduction of Level.3 capability.
Road operators across Australia, informed by their knowledge of the infrastructure on their roads (including line markings and signage) and the capabilities of Level.2 automation systems already appearing in vehicles, may wish to make some input into a nationally consistent operational domain on the road network.
Connected-autonomous vehicles
With Level.3 hands-off-the-wheel driving on the way, it’s envisaged that freeway operators will need to communicate directly to autonomous vehicles, for example to communicate a change in conditions or the operating environment (for example, an emergency incident, congestion event, or lane or freeway closure).
As part of the EastLink trials, connected vehicle transceivers are being installed at three of EastLink’s tolling gantries, to create a section of EastLink enabled for V2X communications.
Initial testing has been focused on verifying the compatibility of connected vehicle communications (5.9 GHz) with the existing DSRC tolling tag communications (5.8 GHz).
Next, the trials program will conduct on-road tests of different message types.
Where to now
EastLink received a Special Commendation award from the Australia & New Zealand Driverless Vehicle Initiative (ADVI) for these trials of automated vehicle technologies.
EastLink will continue to is raise public awareness of automated vehicle capabilities, and will be communicating the progress of the trials via email newsletters to 360,000 EastLink customers, and by media engagement (with extensive coverage already achieved on TV, print, radio, industry and automotive news media).
