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From page 27... ... C H A P T E R 4 Roadway, Driver, Environmental, and Vehicle Data Needs and Limitations to Address Lane Departures Using Naturalistic Driving Study DataBackground This chapter discusses the roadway, driver, environmental, and vehicle factors that must be included to address the research questions outlined in Chapter 2 ("Research Questions," p. Read the entire page →
From page 28... ... 28discusses the review of SHRP 2 Safety Projects S03 and S05 documents that describe the data collection systems for the proposed full-scale naturalistic driving study. The research team's understanding of the relevant data collection sensors and techniques and the expected accuracy and frequency of data collection are summarized. Read the entire page →
From page 29... ... 29Vehicle Factors Needed to Answer Lane Departure Research Questions The following section summarizes vehicle factors necessary to address lane departure research questions, indicates potential sources in the existing data sets, suggests accuracy and frequency needs, and includes comments about accuracy and availability in the existing data sets. Data Element: Vehicle Spatial Position (Latitude, Longitude) Read the entire page →
From page 30... ... 30Figure 4.1. Determination of lane departure and amount of shoulder encroachment.Figure 4.2. Read the entire page →
From page 32... ... 32• Potential source for data element: Existing roadway data sets or from mobile mapping. Roadway and median width could also be measured using forward video from UMTRI when distances were calibrated. Read the entire page →
From page 33... ... 33• Resolution: Once for each spiral. • Comments on extracting data from existing data sets: The team reviewed aerial imagery but could not detect or measure spirals. Read the entire page →
From page 35... ... 35Figure 4.6. Image from DriveCam showing presence and type of rumble strips.(a) Read the entire page →
From page 36... ... 36• Comments on extracting data from existing data sets: A subjective measure of roadway surface condition and roadway irregularities could be obtained from both the VTTI and UMTRI forward video. Measures such as presence of water on the roadway can be determined as shown in Figure 4.8. Read the entire page →
From page 37... ... 37Source: UMTRI RDCW data set. Figure 4.10. Read the entire page →
From page 38... ... 38study, but the detailed results for each driver were unavailable. Acceleration and braking data can be obtained from the data sets, but speed limit information is available neither in the VTTI nor the UMTRI databases. Read the entire page →
From page 39... ... 39driver goes around stalled vehicle on shoulder or passes the vehicle) Read the entire page →
From page 40... ... 40Table 4.2. Roadway Factors Data Element Data Stream Accuracy Frequency Priority Lane width Roadway and shoulder surface type Shoulder and median width Number of lanes, access control, presence and type of median Curve length and radius Superelevation, lane cross slope Curve direction Distance between successive curves Type and characteristics of curve spirals Amount of grade (percent) Read the entire page →
From page 41... ... 41Table 4.4. Exposure Factors Data Element Data Stream Accuracy Frequency Priority AADT Roadway data sets Most current year NA Medium available Time into trip Vehicle data stream NA 10 Hz Medium Amount of time driving on various Vehicle data stream NA 10 Hz High roadway types under different conditions Density Forward/side imagery NA NA High Lane departure crash data State or local crash databases NA NA MediumTable 4.5. Read the entire page →
From page 42... ... 42Table 4.6. Final Rodeo Asset Data Elements Adequate for Lane Departure Research Feature Data Elements Frequency Accuracy Questions Barrier (presumably this includes median barriers and guardrail) Read the entire page →
From page 43... ... 43Table 4.7. Final Rodeo Geometric Data Elements Adequate for Lane Departure Research Feature Data Elements Frequency Accuracy Questions Grade Cross slope Curvature Direction and percent Location Location Roadway cross slope Clear zone cross slope Clear zone width Horizontal PC (point of curvature) Read the entire page →
From page 44... ... 44Table 4.9. Final Rodeo Pavement Condition Data Elements Adequate for Lane Departure Research Feature Data Elements Frequency Accuracy Questions Pavement edge Pavement profile Skid Amount of pavement edge drop-off Location Roughness measures Critical pavement failure Macrotexture Reported at 0.1 mile intervals ±0.5 in. Read the entire page →
From page 45... ... 45be important to compare actual lane width to what is collected by the lane position tracking system to serve as a check. Hence, accurate measurement of lane width is important. Read the entire page →
From page 46... ... 46It may be necessary to determine sign location (signs may be placed or removed after a roadway is scanned using the mobile mapping system) ; it will also be possible to provide a qualitative measure of sign condition and retroreflectivity. Read the entire page →
From page 47... ... 47The wide-view forward video appears to have a fish-eye view that distorts objects and perspective. Although distance and identification of objects may come from other data sources, the fish-eye view could affect the ability to detect nearness of objects, identify objects, and identify sequence of events. Read the entire page →
From page 48... ... 48System output includes the following: – Lane offset, which is the position of the center line of the vehicle with respect to the centerline of the roadway; – Lane width, determined by estimating the width of the marked lane in inches; – Line distance, which is the distance from the center of the vehicle to the right- or left-lane line; and – Probability percentages, which is a measure of the likelihood that the pavement markings exist (serves as a key indicator for the overall reliability of the system) Read the entire page →
From page 49... ... 49Sensor/Element: Sensor to Record Internal Ambient Temperature (Dingus et al., 2008b, Task 7, Appendices A and B) • Description: Record of vehicle cabin temperature. Read the entire page →
From page 50... ... 50Sensor/Element: Instrument Panel View (Dingus et al., 2008a, Task 6) • Description: Provides an over-the-shoulder view of the steering column and instrument panel. Read the entire page →
From page 52... ... 52enough to determine when one or more tires have departed the roadway surface. The planned lane position tracking system for the full-scale study has a stated accuracy of ±0.656 ft (0.2 m) Read the entire page →

From page 27...

... C H A P T E R 4 Roadway, Driver, Environmental, and Vehicle Data Needs and Limitations to Address Lane Departures Using Naturalistic Driving Study DataBackground This chapter discusses the roadway, driver, environmental, and vehicle factors that must be included to address the research questions outlined in Chapter 2 ("Research Questions," p.