Work Zone - 3.01 Travel Time - Revision history

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Solution 3.5: Control Delay Signalized Intersection: formatting

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Solution 3.2: Freeway: formatting

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Solution 3.3 Urban Freeway, Queue Delay: formatting

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Solution 3.2: Freeway: formatting

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Solution 3.1: Freeway: formatting

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	===B. Travel Time Determination===		===B. Travel Time Determination===
		+	Similar to uninterrupted flow facilities, the initial travel time (before construction) should be computed or measured. Existing travel time runs may be completed to verify the existing conditions, especially to validate the existing travel time reported from software tools. The travel time estimates may be performed using various techniques summarized in [[Work Zone - 3.03 Mobility Analysis Tools#3.03.07 Travel Demand Models and Tools\|Section 3.03.07 Travel Demand Models and Tools]].
		+
		+	==3.01.05 Detour Routes==
		+	The determination of travel time delay for detour routes includes a comparison of the initial travel time on the original route (before construction) compared to the travel time during construction. The capacity conditions along the detour route will be important to consider, especially regarding the amount of traffic diverted to the detour route. If the detour route consists of traffic signals or other interrupted flow facilities, an evaluation of the intersection operations, including the detour traffic, may be necessary.
		+
		+	For detour routes with the necessary capacity to accommodate the diverted traffic volumes, the travel time along the detour route may be established as the travel distance divided by the average speed. A travel time run may be performed during the design development of the project to establish the anticipated detour travel time. Similarly, the detour travel time may be quickly determined using online map guidance tools, simply placing two points on a map, and routing the path along the detour route.
		+
		+	If intersection control delay is a particular concern for the detour route, the delay may be computed using software tools such as Synchro and added to the previously calculated detour travel time. This level of analysis should be completed when shutting off or detouring a major roadway movement, or the detour route is already at or above capacity, with existing traffic volumes.
		+
		+	==Categories==
		+	* [[Work Zone - Chapter 3 \| Chapter 3: Mobility Analysis]]
		+	* [[Work Zone - Index \| Work Zone Safety and Mobility Manual Index]]

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 <big>'''''d<sub>1</sub> &#61; <sup>0.5 &times; 80(1 &#8722; 0.6)<sup>2</sup></sup>&#8725;<sub>1 &#8722; [0.98 &times; 0.6]</sub> &#61; 15.5 sec'''''</big></div></br>
 The term for incremental delay '''''d<sub>2</sub>''''' is computed for the time interval for one hour, thus '''''T = 1''''' in the following equation: <div style="text-align: center;"></br>
-<big>'''''d<sub>2</sub> &#61; 900 &times; 1{(0.98 &#8722; 1)+[(0.98 &#8722; 1)<sup>2</sup> + ( <sup>4 &times; 0.98</sup>&#8725;<sub>870 &times; 1</sub> )]<sup><sup>1</sup>&#8725;<sub>2</sub></sup> } &#61; 45 sec'''''</big></div></br>
+<big>'''''d<sub>2</sub> &#61; 900 &times; 1{(0.98 &#8722; 1) + [(0.98 &#8722; 1)<sup>2</sup> + ( <sup>4 &times; 0.98</sup>&#8725;<sub>870 &times; 1</sub> )]<sup><sup>1</sup>&#8725;<sub>2</sub></sup> } &#61; 45 sec'''''</big></div></br>
 The total control delay for this lane group is  <div style="text-align: center;"></br>
 <big>'''''d = 15.5 + 45 = 60.5 sec'''''</big></div>
 ===B. Travel Time Determination===

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 Multiply the AADT by the DHV % to obtain the DHV.  TDMS indicates that the DHV% for this segment is 12%:
-'''''(5,950 veh) × (12% DHV) = 714 vph'''''
+''(5,950 veh) × (12% DHV) = 714 vph''
 Use the table for Appendix H. Capacity in Traffic Regulator Zones to determine the maximum allowable length of the work zone given the 45 mph speed limit.  The design hour has 714 vph.  Utilizing the table for Appendix H. Capacity in Traffic Regulator Zones traffic regulation operation will result in delays of 10 minutes or less (714 is less than 725 which is capacity at 2.0 miles). Confirm hourly volume calculation with hourly traffic volumes if available.

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 =====Solution 3.2: Freeway=====
 The lane capacity is computed by starting with the base capacity ('''''C<sub>b</sub>''''') for a 3 lane freeway to a 2 lane freeway 1700 vphpl. Adjustments are applied for close proximity intense work activity ('''''I<sub>g</sub>''''' = -100), ('''''I<sub>wt</sub>''''' = 50), ('''''I<sub>wa</sub>''''' = -150), side clearance ('''''f<sub>sc</sub>''''' = 0.95), percentage trucks ('''''f<sub>hv</sub>''''' = 0.95). The adjusted capacity for two open lanes is: <div style="text-align: center;"></br>
-<big>'''''C<sub>a</sub> &#61; {[(1700 − 100 + 50 −1 00) × 0.95 × 0.95] ×2} &#61; 2798 vph or 1399 vphpl'''''</big></div>
+<big>'''''C<sub>a</sub> &#61; {[(1700 &minus; 100 + 50 &minus; 100) × 0.95 × 0.95] × 2} &#61; 2798 vph or 1399 vphpl'''''</big></div>
 ===B. Traffic Demand Determination===

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 =====Solution 3.3 Urban Freeway, Queue Delay=====
 The adjusted mainline capacity estimated earlier is 2798 vph.  The accumulated queue for the time period (hour) is the demand that exceeds the capacity.</br> <div style="text-align: center;">
-<big>'''''Q = 3000 - 2798 = 202 veh''''' </big></div></br>
+<big>'''''Q = 3000 &#8722; 2798 = 202 veh''''' </big></div></br>
 The queue delay is:</br> <div style="text-align: center;">
 <big>'''''t &#61; <sup>202</sup>&#8725;<sub>2798</sub> &times; 60 &#61; 4.33 min''''' </big></div></br>

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 =====Solution 3.1: Freeway=====
-The lane capacity is computed by starting with the base capacity (''C<sub>b</sub>'') for a 2 lane freeway to a 1 lane freeway 1550 vphpl. The adjustment factor applied for geometry includes use of a crossover, with a > 3 foot shift, and traffic driving on the shoulder.  Since we are only allowed to use one factor ''I<sub>g</sub>'' = -100 (could range from 100 to 150). Although the work type is reconstruction, it is not in close proximity to the maintained traffic since it occurs on the closed bound of the freeway (''I<sub>wt</sub>'' = 100). The adjustment factors applied for work activity (''I<sub>wa</sub>'' = 50), lane width (''f<sub>lw</sub>'' = 0.95), side clearance (''f<sub>sc</sub>'' = 0.95), and percent trucks (''f<sub>hv</sub>'' = 0.98). The adjusted capacity is:
+The lane capacity is computed by starting with the base capacity ('''''C<sub>b</sub>''''') for a 2 lane freeway to a 1 lane freeway 1550 vphpl. The adjustment factor applied for geometry includes use of a crossover, with a > 3 foot shift, and traffic driving on the shoulder.  Since we are only allowed to use one factor '''''I<sub>g</sub>''''' = -100 (could range from 100 to 150). Although the work type is reconstruction, it is not in close proximity to the maintained traffic since it occurs on the closed bound of the freeway ('''''I<sub>wt</sub>''''' = 100). The adjustment factors applied for work activity ('''''I<sub>wa</sub>''''' = 50), lane width ('''''f<sub>lw</sub>''''' = 0.95), side clearance ('''''f<sub>sc</sub>''''' = 0.95), and percent trucks ('''''f<sub>hv</sub>''''' = 0.98). The adjusted capacity is: <div style="text-align: center;"></br>
+<big>'''''C<sub>a</sub> &#61; [(1550 − 100 + 100 + 50) × 0.95 × 0.95 × 0.98] &#61; 1415 vph'''''</big></div>
 =====Example 3.2: Freeway=====

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 Table 3-1 Base Mainline Capacity and Table 3-2 Capacity Adjustment Factors should be used to estimate the capacity for each open lane.  Apply factors known to adjust the base work zone capacity.
-To begin the development of traffic control options, determine the number of lanes needed to handle the expected demand.  An early check of available roadway capacity is critical as the vast majority of additional delay due to a work zone occurs when demand exceeds capacity for any appreciable length of time.  The Highway Capacity Manual (HCM) Equation 10-9 can be used to determine the resulting adjusted capacity of the roadway lane:
+To begin the development of traffic control options, determine the number of lanes needed to handle the expected demand.  An early check of available roadway capacity is critical as the vast majority of additional delay due to a work zone occurs when demand exceeds capacity for any appreciable length of time.  The Highway Capacity Manual (HCM) Equation 10-9 can be used to determine the resulting adjusted capacity of the roadway lane: <div style="text-align: center;"></br>
-'''''C<sub>a</sub> = {[(C<sub>b</sub> + I<sub>g</sub> + I<sub>wt</sub> + I<sub>wa</sub> ) &times; f<sub>hv</sub> &times; f<sub>lw</sub> &times; f<sub>sc</sub> ] &times; N} &minus; R '''''
+<big>'''''C<sub>a</sub> = {[(C<sub>b</sub> + I<sub>g</sub> + I<sub>wt</sub> + I<sub>wa</sub> ) &times; f<sub>hv</sub> &times; f<sub>lw</sub> &times; f<sub>sc</sub> ] &times; N} &minus; R '''''</big></div></br>
 Where:

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 The following formula can be used to compute the delay time for a vehicle at the back of the queue: <div style="text-align: center;"></br>
-'''''t = ( <sup>Q</sup>&#8725;<sub>C<sub>a</sub></sub> ) &times; 60'''''</div></br>
+<big>'''''t = ( <sup>Q</sup>&#8725;<sub>C<sub>a</sub></sub> ) &times; 60'''''</big></div></br>
 Where:
 </br>
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 =====Solution 3.3 Urban Freeway, Queue Delay=====
 The adjusted mainline capacity estimated earlier is 2798 vph.  The accumulated queue for the time period (hour) is the demand that exceeds the capacity.</br> <div style="text-align: center;">
-''Q = 3000 - 2798 = 202 veh'' </div></br>
+<big>'''''Q = 3000 - 2798 = 202 veh''''' </big></div></br>
 The queue delay is:</br> <div style="text-align: center;">
-''t &#61; <sup>202</sup>&#8725;<sub>2798</sub> &times; 60 &#61; 4.33 min </div></br>
+<big>'''''t &#61; <sup>202</sup>&#8725;<sub>2798</sub> &times; 60 &#61; 4.33 min''''' </big></div></br>
 ====Table 33: Per Lane Capacity for Signalized Flow====

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 The relative nearness of the traffic demand to capacity is related using the V /C ratio.  The V/C ratio may be used as a performance measure for the work zone operations.
-The speed delay attributable to the work zone can be computed as the difference in the travel time during construction and before construction.  The following formula may be used to compute speed delay:
+The speed delay attributable to the work zone can be computed as the difference in the travel time during construction and before construction.  The following formula may be used to compute speed delay:<div style="text-align: center;"></br>
-<div style="text-align: center;"></br>
+<big>'''''t = D &times; ( <sup>1</sup>&#8725;<sub>U<sub>wz</sub></sub> &minus; <sup>1</sup>&#8725;<sub>U<sub>i</sub></sub> ) &times; 60'''''</big></div></br>
 Where:
 </br>