ITS Benefits >> Signal Priority operations shown to improve connected bus travel times by 8.2 percent and connected truck travel times by 39.7 percent.

Dynamic Mobility Applications (DMA’s) Multi-Modal Intelligent Traffic Signal Systems (MMITSS) application bundle uses advanced communications and data from connected vehicle technology to facilitate efficient travel for various vehicle-types and pedestrians through signalized corridors.
A MMITSS prototype was developed and field tested featuring three component applications:
  • Intelligent Traffic Signal System (I-SIG)
  • Transit Signal Priority (TSP)
  • Freight Signal Priority (FSP)

The study assessed overall system-wide delay and throughput considering various forms of control and signal priority implemented in an isolated intersection or in network environment.

Read more: ITS Benefits >> Signal Priority operations shown to improve connected bus travel times by 8.2...

ITS Benefits >> Forward collision warning systems with adaptive braking and anticipatory collision safety features can mitigate severity in 53 percent of rear-end collisions.

This paper examined the effectiveness of forward collision assistance systems used to help drivers avoid rear-end collisions and mitigate crash severity. The systems evaluated included one or more of the following: FCW (forward collision warning), EBA (emergency brake assist), and AEB (autonomous emergency braking). AEB included subcategories of CMB (autonomous collision mitigation braking) and CIB (autonomous collision imminent braking).

Findings in this paper were based on: 1) A driving simulator experiment that examined the behavior of real world drivers equipped with forward collision warning and automated brake assist systems. 2) Field tests that looked at equipment performance and changes collision avoidance in the real world; 2) Analyses of Spare Part Calls from an OEM that can estimated changes safety based on changes in spare parts needed for repairs; 3) Analyses of property damage liability, collision, bodily injury liability, personal injury protection and medical payment coverages associated with these technologies.

METHODOLOGY

Driving Simulator Tests
The effectiveness of a driver braking assistance system was assessed using a Berlin dynamic driving simulator. The system was designed to use radar to monitor vehicle headways, warn a driver if the headway was too small, and then optimizes brake force if needed to mitigate or avoid a rear-end collision.

A total of 110 ordinary drivers were recruited to participate and cope with three types of driving situations that often lead to rear-end collisions. Half the drivers drove a vehicle equipped with conventional Brake Assist System (BAS - shortens stopping distance by boosting brakes when maximum braking is applied), and the other half used BAS PLUS (conventional brake assistance plus enhanced braking based on input from forward radar system).

Field Tests
Field testing was performed on vehicles driven by non-expert drivers in Europe, United States, Japan, and South Africa. Data were collected from over 1 million km driven. Activation events were recorded using in-vehicle video and on-board data collection systems in each test car. These vehicles were equipped with both forward collision warning and adaptive brake assist systems.

Analyses of Spare Part Calls
The evaluation was based on changes in the rate of spare parts calls for the S-Class model 221 delivered by Mercedes-Benz in Germany between launch and end of 2008. In this period about 40,000 cars were sold and registered in Germany. About 40 percent of these cars were equipped with forward radar scanning adaptive cruise control and forward collision warning systems, anticipatory seat belt tensioners, adaptive brake and brake assistance, and parking assistance. The remaining 60 percent were equipped with parking assistance only.

Real-World Effectiveness With Insurance Data
Insurance claims data were analyzed for collision avoidance systems offered on Acura, Mercedes-Benz and Volvo passenger vehicles. The following specifications were excerpted from the source report.

"Acura with auto brake" includes a forward collision mitigation system that uses visual and auditory alerts to warn drivers when speeds and distance data indicate crash risk with a leading vehicle. If the driver does not respond by reducing speed, the system will automatically tug at the seat belt to get the driver’s attention and begin braking to mitigate severity , but probably not prevent a crash. This mitigation strategy becomes functional at speeds over 15 km/h and deactivates when speed drops below 15 km/h. It was bundled with an adaptive cruise control system.

"Mercedes-Benz with auto brake" means that the vehicles were equipped with forward radar scanning adaptive cruise control as well as a driver assistance system that have a low end operational speed threshold of 30 km/h.

"Volvo vehicles without auto brake" use adaptive cruise control and forward collision warning radar sensors mounted on bumpers to detect collision risk. Auditory and visual alerts, such as red lights in a heads-up windshield display, are provided to drivers. If the driver brakes the warnings are canceled. The forward collision warning system is active only between speeds of 30 and 180 km/h. Vehicles equipped with forward collision warning also have adaptive cruise control and distance alerts. "Volvo vehicles with auto brake" have a forward collision warning system that includes some autonomous emergency braking.

FINDINGS

Driver Simulator Test
Results showed that the combination of forward collision warning (FCW) and BAS PLUS lead to a 75 percent lower accident rate (combined) compared to the conventional BAS. For those subjects who reacted too late to avoid the accident, BAS PLUS produced a mitigating effect: impact speed was reduced by 35 percent on average.

Field Test
No forward collision warning activation without any driver reaction was observed. Hence the audible/visual warning, a combination of warning tone and icon, proved to be very effective. Interestingly 44 percent of all drivers were already braking when a forward collision warning occurred. Of the drivers who responded to forward collision warning by applying the brake:

  • 65 percent acted within 0.4 second after the warning
  • 87 percent acted within 0.8 second after the warning
  • 97 percent acted within 1.0 second after the warning

Data collected specifically from the Mercedes-Benz Collision Prevention Assist (CPA) system that includes a forward collision avoidance, and adaptive braking and brake assist was found to be able to address 71 percent of all rear-end pre-crash situations.

Analyses of Spare Part Calls
The rate of repairs of front-end bumpers was reduced by 5 percent, the repair rate of a front-end bumper in combination with a cross member dropped by 15 percent and repairs involving front-end bumper, cross and longitudinal member assembly dropped by 22 percent. These data show that forward radar scanning adaptive cruise control with the included driver assistance features including anticipatory seat belt tensioners was effective at reducing the number and severity of frontal crashes.

Real-World Effectiveness With Insurance Data
Accident research shows that drivers do not always react as quickly as is necessary in critical moments. Using driver assistance packages that support FCW and advanced braking systems 53 percent of all rear-end collision could be mitigated in their severity and 35 percent could be avoided. The risk for an occupant of the striking car of being seriously injured is reduced by at least 35 percent. Claim frequency reduced by 14.3 percent in the insurance coverage property damage liability.

Read more: ITS Benefits >> Forward collision warning systems with adaptive braking and anticipatory...

ITS Benefits >> Sixty-six percent of drivers changed their route following information provided by Iowa 511 system.

First launched by the Iowa Department of Transportation in 2002, Iowa 511 provides real-time information on road traffic conditions, accidents, road closures, road construction, weather conditions, and other information of interest to the public. As of 2015, the Iowa 511 system disseminates information to the public via phone service, websites, social networks, and mobile applications (apps). A study carried out by the Center for Transportation Research at Iowa State University assessed the Iowa 511 Traveler Information System using survey results and usage data for the 511 phone, websites, and mobile apps maintained by the Iowa Department of Transportation (DOT). As part of the assessment, the public was surveyed to gain insight into the usage of Iowa 511 within the state and to analyze the system's effect on driver behavior and driving patterns.

Survey Methodology:
An online survey questionnaire was delivered to current Iowa 511 users and Iowa DOT employees. Survey questions addressed the sources for obtaining information on road construction and closures, weather-related delays, and travel times/routes and also included questions regarding driving patterns and basic demographics. The survey was delivered via email and was posted on multiple online portals where results were collected from May 20, 2015 until June 15, 2015. In total, 362 respondents, of which 296 were Iowa DOT employees, completed the survey during this timeframe.

Survey Findings:

  • About 78 percent (283/362) of survey respondents had used Iowa 511. Of those users, Iowa 511 had the most impact on their route choices and departure times:
  • 66 percent (186/283) had changed the route for their trips.
  • 63 percent (178/283) had changed their departure times.
  • 49 percent (138/283) responded that Iowa 511 had helped them to better prepare for their trips.

Read more: ITS Benefits >> Sixty-six percent of drivers changed their route following information provided...

ITS Benefits >> Tractor-trailor platooning enabled by V2V communications demonstrates fuel savings up to 9.7 percent

A research project funded by the Department of Energy evaluated the fuel consumption reduction of a pair of platooned Class 8 tractor-trailers on a test track over a range of highway truck speeds, following distances, and weights that would represent the conditions of driving on public roads. The platooning demonstration system consists of radar systems, Dedicated Short-Range Communication (DSRC) vehicle-to-vehicle (V2V) communications, vehicle braking and torque control interface, cameras and driver displays. The throttle and braking on the rear truck are controlled using a combination of inputs including, but not limited to: radar-measured distance, GPS locations and speeds of both vehicles, lead vehicle wheel-based speed, torque request and braking application. The system does not control lateral position so the trailing truck driver is still responsible for steering, which is a possible source of variation in the tests.

Methodology

Testing took place at the Continental Tire Proving Grounds in Uvalde, Texas, on an 8.5 mile asphalt oval with several small grade changes rather than a zero grade environment. A series of ten modified SAE Type II J1321 fuel consumption track tests were performed to document the fuel consumption of the two platooned vehicles and a control vehicle at varying steady-state speeds, following distances, and gross vehicle weights (GVWs). The steady-state speeds ranged from 55 mph to 70 mph, the following distances ranged from a 20-ft to 75-ft, and the GVWs were 65K lbs and 80K lbs. All tractors involved had U.S. Environmental Protection Agency (EPA) SmartWay-compliant aerodynamics packages installed, and the trailers were equipped with side skirts. Fuel consumption savings were recorded through methods prescribed in SAE J1321. The effects of vehicle speed, following distance, and GVW on fuel consumption were then analyzed.

Findings

  • The lead tractor consistently demonstrated an improvement in average fuel consumption reduction as following distance decreased, with results showing 2.7 percent to 5.3 percent fuel savings at a GVW of 65k.
  • The trailing vehicle achieved fuel consumption savings ranging from 2.8 percent to 9.7 percent.
  • Tests during which the engine cooling fan did not operate achieved savings of 8.4 percent to 9.7 percent.
  • "Team" fuel savings, considering the platooned vehicles as one, ranged from 3.7 percent to 6.4 percent, with the best combined result being for 55 mph, 30-ft following distance, and 65k GVW.

Read more: ITS Benefits >> Tractor-trailor platooning enabled by V2V communications demonstrates fuel...

Nissan Sentra, Infiniti QX60 earn top award

ARLINGTON, Va. — Two vehicles from Nissan Motor Co. join the ranks of Top Safety Pick+ winners after earning superior ratings for front crash prevention.

The Nissan Sentra, a small car, and the Infiniti QX60, a midsize luxury SUV, both have good ratings in the Insurance Institute for Highway Safety's five crashworthiness tests. Their optional front crash prevention systems only recently became available for testing.

The Nissan Sentra, a small car, and the Infiniti QX60, a midsize luxury SUV, both have good ratings in the Insurance Institute for Highway Safety's five crashworthiness tests. Their optional front crash prevention systems only recently became available for testing.

In the 12 mph IIHS track test, the Sentra avoided a collision completely. In the 25 mph test, the car's impact speed was reduced by an average of 10 mph.

The QX60 avoided a collision in both tests.

Both vehicles also receive credit for forward collision warning components in their front crash prevention systems that meet National Highway Traffic Safety Administration criteria.

To qualify for Top Safety Pick+, the Institute's highest award, a vehicle must earn good ratings in the small overlap front, moderate overlap front, side, roof strength and head restraint tests, plus an advanced or superior rating for front crash prevention.

With the addition of the Sentra and QX60, Nissan Motor Co. has a total of six vehicles that qualify for the award.

Read more: Nissan Sentra, Infiniti QX60 earn top award

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