Environmental Project No. 1022 – Test cases for control of Nord2000

Test cases for control of Nord2000

3 Test Cases for a Curved Road

Ten test cases have been included for the curved road shown in Figure 1. The test cases are based on test cases used for the previous Nordic road traffic model given in [4]. The test cases include 8 receiver positions denoted 1 to 8. For each of the receiver Positions 4 and 5 two test cases have been defined concerning the definition of the thick screen between Positions 4 and 5. In the first case the thick screen is assumed to be a building with vertical facades flat roof and an energy reflection coefficient of 1 (the case numbers are 4-1 and 5-1). In the second case the thick screen is assumed to be an embankment with the same flat top as the building, but sloping faces with a slope gradient of 0.5 (the case numbers are 4-2 and 5-2). The embankment is covered with grass.

The dashed lines in Figure 1 are ground level contours, and the number next to the contour is the ground level in metres. The ground level of the road is 0, i.e. the road is below the terrain surface at Position 1 and elevated above the ground at Position 8.

The road has two lanes, each 5 m wide, and the vehicles are driving in the middle of each lane. The number of vehicles is 10,000 per day, and the traffic is distributed equally on the two lanes. 90% of the traffic is light vehicles (category-1) while 10% is heavy vehicles distributed evenly on category 2 and 3. The speeds of the light and heavy vehicles are 90 and 70 km/h and the axle widths are 1.5 and 2.5 m, respectively. The distance between the source points along the lane is 10 m for receiver Position 5, 25 m for receiver Position 3, and 50 m for the rest of the receiver positions. If the lane is higher or lower than the surrounding terrain, the terrain is decreasing or increasing, respectively, starting at the edge of the lane with a slope of 45° perpendicular to the road.

The receiver distances shown in Figure 1 are measured from the centre line of the road whereas the distances to the screens are measured from the nearest edge of the road. The thick screen at Position 4 is 3 m high and 3 m wide, and the distance from the road edge to the middle of the screen is 10 m. The thin screen at Position 3 is 3 m high, and the distance to the road edge is 5 m.

The road is assumed to be extended infinitely at the lower and upper end in Figure 1.

The coordinates of the objects in Figure 1 (road centre line, barriers, calculation points, terrain lines) can be found in the Excel spreadsheet file containing the calculation results

Figure 1: Plan view of road and surroundings.

Figure 1: Plan view of road and surrounding

The ground surface is assumed to have a flow resistivity of 200 kNsm^-4 (impedance class D) and no roughness (class N). The road surface is assumed to have a flow resistivity of 20000 kNsm^-4 (impedance class G).

The receiver height is 1.5 m except in Position 7 where the height is 3.5 m.

The propagation parameters are:

t₀ = 15°C
RH = 70%
z₀ = 0.05 m
z_u = 10 m
u = 0, and ±3 m/s
φ_u = 315° re north
s_u = 0.5 m/s
Δt/Δz = 0 K/m
s_Δt/Δz = 0 K/m
C_v² = 0.12 m^4/3/s²
C_t² = 0.008 K/s²

The wind direction φ_u = 315° indicates that the wind direction is perpendicular to the upper part of the road. A wind speed of -3 m/s indicates the opposite wind direction (135°). Therefore, 3 m/s indicates downwind in Positions 1, 3, and 4 and upwind in Positions 2 and 5.

The results of the 10 cases are given in the Excel spreadsheet "TestCurvedRoad.xls" with one worksheet for each test case. An example of a sheet is shown in Appendix B (Receiver Position 1). For information, calculation results for light and heavy vehicles separately are given in two extra worksheets for each case.