![](media/image1.png)

Final Site Report

######## **[Evaluation of Travel]{.smallcaps}**

**[Time Methods to Support]{.smallcaps}**

**[Mobility Performance]{.smallcaps}**

**[Monitoring]{.smallcaps}**

**[World Trade Bridge]{.smallcaps}**

To

Office of Freight Mgt. and Operations

Federal Highway Administration

U.S. Department of Transportation

Washington, DC 20590

 April 2002

**Border Crossing Freight Delay Data Collection and Analysis**

**FY 2001 Data Collection Laredo Crossing**

Site Description

The World Trade Crossing (International Bridge 4) in Laredo, Texas is
the most important truck crossing on the United States/Mexican border.
Texas border crossings account for most of the truck traffic and the
Laredo crossing alone represents over 60% of the truck traffic crossing
the border between Texas and Mexico. Table 1 shows truck traffic for
2000 crossing the border from Mexico to the United States. The World
Trade bridge crosses the Rio Grande River that separates Laredo, Texas
from Nuevo Laredo, Tamaulipas, Mexico and provides a link between I-35
in the United States with such Mexican cities as Monterrey and Mexico
City. Most (up to 90%) of the truck traffic at the World Trade Bridge in
Laredo consists of "drayage." That is, short distance shipments between
warehouses in Laredo and Nuevo Laredo. Typically, long distance trucks
in either Mexico or the United States unload their cargos at a warehouse
where it is transferred to a short haul truck for the trip across the
border. Other shipments move directly from a factory near the border in
Mexico to a warehouse across the border in Texas or from a warehouse in
Texas to a factory in Mexico. These short haul trucks usually make up to
three trips a day across the border. Figure 1 shows a map of the general
region in Texas and Mexico that provides access to the border. Figure 2
shows the location of the World Trade Bridge within the city of Laredo.

Data collection activities took place at the World Trade Bridge border
crossing on Tuesday October 30^th^, Wednesday October 31^st^ and
Thursday November 1^st^, 2001 for approximately ten hours each day. The
times of data collection were selected to correspond to the daylight
hours of operations at the bridge. The World Trade Bridge operates from
8:00 AM to 12:00 Midnight.

Inbound trucks (northbound) traveling towards the United States, leave
Mexico pass through the export booths and proceed across the bridge into
Texas and towards U.S. Customs. At Customs, the vehicles pass through
primary inspection and after a secondary inspection, either proceed to
special inspections (about 15% to 20% of the trucks) or leave Customs
through the final inspection booths.

Outbound trucks (southbound) traveling towards Mexico, use Loop 20,
which provides access to the World Trade Bridge. It can be accessed
directly from I-35 or from the south from Mines Road. Loop 20
approaching the bridge is a new divided highway built specifically as an
access road for the World Trade Bridge. Close to the border, the number
of lanes expands to eight to enable the vehicles to proceed through the
toll booths. The trucks cross the bridge and enter Mexico through import
booths. Ordinarily, the Mexicans have up to ten booths operating. Most
trucks pass through the import booths without much delay (no more than
90 seconds) and a small percentage are diverted to the secondary
inspection facilities. At secondary inspection, trucks can undergo
further papers checks and/or physical inspection at truck bays or in the
parking area.

<table>
<colgroup>
<col style="width: 20%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 0%" />
<col style="width: 4%" />
<col style="width: 0%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="12"><h6
id="table-1.-truck-crossings-from-mexico-into-the-united-states-for-2000">Table
1. Truck Crossings from Mexico into the United States for 2000</h6>
<p id="incoming-truck-crossings-us-mexican-border-for-2000"
class="heading">Incoming Truck Crossings, US-Mexican Border for
2000</p></td>
<td colspan="4"></td>
</tr>
<tr class="even">
<td><strong>PORT NAME</strong></td>
<td><strong>January</strong></td>
<td><strong>February</strong></td>
<td><strong>March</strong></td>
<td><strong>April</strong></td>
<td><strong>May</strong></td>
<td><strong>June</strong></td>
<td><strong>July</strong></td>
<td><strong>August</strong></td>
<td><strong>September</strong></td>
<td colspan="3"><strong>October</strong></td>
<td><strong>November</strong></td>
<td><strong>December</strong></td>
<td><strong>Total</strong></td>
</tr>
<tr class="odd">
<td><strong>Arizona, Total</strong></td>
<td><strong>35,979</strong></td>
<td><strong>35,995</strong></td>
<td><strong>38,278</strong></td>
<td><strong>33,418</strong></td>
<td><strong>32,354</strong></td>
<td><strong>25,502</strong></td>
<td><strong>19,328</strong></td>
<td><strong>21,160</strong></td>
<td><strong>20,325</strong></td>
<td colspan="3"><strong>24,608</strong></td>
<td><strong>28,051</strong></td>
<td><strong>29,267</strong></td>
<td><strong>344,265</strong></td>
</tr>
<tr class="even">
<td>Douglas, AZ</td>
<td>2,868</td>
<td>2,913</td>
<td>2,563</td>
<td>2,171</td>
<td>2,696</td>
<td>2,983</td>
<td>2,534</td>
<td>2,946</td>
<td>2,712</td>
<td colspan="3">3,051</td>
<td>3,158</td>
<td>2,999</td>
<td>33,594</td>
</tr>
<tr class="odd">
<td>Lukeville, AZ</td>
<td>269</td>
<td>295</td>
<td>363</td>
<td>383</td>
<td>401</td>
<td>331</td>
<td>342</td>
<td>257</td>
<td>269</td>
<td colspan="3">349</td>
<td>298</td>
<td>283</td>
<td>3,840</td>
</tr>
<tr class="even">
<td>Naco, AZ</td>
<td>683</td>
<td>912</td>
<td>1,183</td>
<td>725</td>
<td>713</td>
<td>U</td>
<td>704</td>
<td>814</td>
<td>718</td>
<td colspan="3">995</td>
<td>980</td>
<td>710</td>
<td>9,137</td>
</tr>
<tr class="odd">
<td>Nogales, AZ</td>
<td>27,659</td>
<td>27,525</td>
<td>29,066</td>
<td>26,509</td>
<td>25,386</td>
<td>19,266</td>
<td>13,075</td>
<td>14,359</td>
<td>13,595</td>
<td colspan="3">16,448</td>
<td>20,151</td>
<td>21,655</td>
<td>254,694</td>
</tr>
<tr class="even">
<td>Sasabe, AZ</td>
<td>269</td>
<td>235</td>
<td>184</td>
<td>185</td>
<td>174</td>
<td>186</td>
<td>178</td>
<td>208</td>
<td>271</td>
<td colspan="3">211</td>
<td>430</td>
<td>121</td>
<td>2,652</td>
</tr>
<tr class="odd">
<td>San Luis, AZ</td>
<td>4,231</td>
<td>4,115</td>
<td>4,919</td>
<td>3,445</td>
<td>2,984</td>
<td>2,736</td>
<td>2,495</td>
<td>2,576</td>
<td>2,760</td>
<td colspan="3">3,554</td>
<td>3,034</td>
<td>3,499</td>
<td>40,348</td>
</tr>
<tr class="even">
<td><strong>California, Total</strong></td>
<td><strong>76,230</strong></td>
<td><strong>82,463</strong></td>
<td><strong>90,509</strong></td>
<td><strong>80,585</strong></td>
<td><strong>88,938</strong></td>
<td><strong>98,319</strong></td>
<td><strong>87,890</strong></td>
<td><strong>92,603</strong></td>
<td><strong>85,122</strong></td>
<td colspan="3"><strong>89,017</strong></td>
<td><strong>83,549</strong></td>
<td><strong>76,321</strong></td>
<td><strong>1,031,546</strong></td>
</tr>
<tr class="odd">
<td>Andrade, CA</td>
<td>105</td>
<td>159</td>
<td>181</td>
<td>126</td>
<td>152</td>
<td>136</td>
<td>111</td>
<td>92</td>
<td>82</td>
<td colspan="3">117</td>
<td>125</td>
<td>131</td>
<td>1,517</td>
</tr>
<tr class="even">
<td>Calexico, CA*</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td>U</td>
<td colspan="3">U</td>
<td>U</td>
<td>U</td>
<td>U</td>
</tr>
<tr class="odd">
<td>Calexico East, CA</td>
<td>22,405</td>
<td>23,372</td>
<td>25,684</td>
<td>21,026</td>
<td>22,962</td>
<td>29,155</td>
<td>22,182</td>
<td>24,003</td>
<td>21,297</td>
<td colspan="3">23,137</td>
<td>22,285</td>
<td>21,303</td>
<td>278,811</td>
</tr>
<tr class="even">
<td>Otay Mesa/San Ysidro, CA</td>
<td>49,378</td>
<td>53,898</td>
<td>58,836</td>
<td>54,239</td>
<td>59,955</td>
<td>63,547</td>
<td>60,484</td>
<td>62,780</td>
<td>58,640</td>
<td colspan="3">60,034</td>
<td>56,122</td>
<td>50,427</td>
<td>688,340</td>
</tr>
<tr class="odd">
<td>Tecate, CA</td>
<td>4,342</td>
<td>5,034</td>
<td>5,808</td>
<td>5,194</td>
<td>5,869</td>
<td>5,481</td>
<td>5,113</td>
<td>5,728</td>
<td>5,103</td>
<td colspan="3">5,729</td>
<td>5,017</td>
<td>4,460</td>
<td>62,878</td>
</tr>
<tr class="even">
<td><strong>New Mexico, Total</strong></td>
<td><strong>2,282</strong></td>
<td><strong>2,711</strong></td>
<td><strong>3,009</strong></td>
<td><strong>3,373</strong></td>
<td><strong>3,072</strong></td>
<td><strong>3,036</strong></td>
<td><strong>2,880</strong></td>
<td><strong>3,672</strong></td>
<td><strong>3,767</strong></td>
<td colspan="3"><strong>3,438</strong></td>
<td><strong>2,906</strong></td>
<td><strong>2,345</strong></td>
<td><strong>36,491</strong></td>
</tr>
<tr class="odd">
<td>Columbus, NM</td>
<td>193</td>
<td>212</td>
<td>243</td>
<td>233</td>
<td>315</td>
<td>206</td>
<td>316</td>
<td>916</td>
<td>956</td>
<td colspan="3">601</td>
<td>197</td>
<td>157</td>
<td>4,545</td>
</tr>
<tr class="even">
<td>Santa Teresa, NM</td>
<td>2,089</td>
<td>2,499</td>
<td>2,766</td>
<td>3,140</td>
<td>2,757</td>
<td>2,830</td>
<td>2,564</td>
<td>2,756</td>
<td>2,811</td>
<td colspan="3">2,837</td>
<td>2,709</td>
<td>2,188</td>
<td>31,946</td>
</tr>
<tr class="odd">
<td><strong>Texas, Total</strong></td>
<td><strong>242,935</strong></td>
<td><strong>256,127</strong></td>
<td><strong>282,616</strong></td>
<td><strong>241,863</strong></td>
<td><strong>277,312</strong></td>
<td><strong>272,753</strong></td>
<td><strong>247,327</strong></td>
<td><strong>293,468</strong></td>
<td><strong>257,554</strong></td>
<td colspan="3"><strong>271,225</strong></td>
<td><strong>249,431</strong></td>
<td><strong>220,666</strong></td>
<td><strong>3,113,277</strong></td>
</tr>
<tr class="even">
<td>Brownsville, TX</td>
<td>24,915</td>
<td>25,223</td>
<td>26,860</td>
<td>24,993</td>
<td>27,771</td>
<td>27,756</td>
<td>25,248</td>
<td>27,689</td>
<td>23,784</td>
<td colspan="3">23,902</td>
<td>22,183</td>
<td>18,914</td>
<td>299,238</td>
</tr>
<tr class="odd">
<td>Del Rio, TX</td>
<td>4,979</td>
<td>5,117</td>
<td>5,689</td>
<td>4,768</td>
<td>5,420</td>
<td>5,436</td>
<td>4,691</td>
<td>5,525</td>
<td>4,984</td>
<td colspan="3">5,444</td>
<td>5,120</td>
<td>4,055</td>
<td>61,228</td>
</tr>
<tr class="even">
<td>Eagle Pass, TX</td>
<td>8,402</td>
<td>9,164</td>
<td>9,481</td>
<td>8,549</td>
<td>9,876</td>
<td>8,941</td>
<td>8,361</td>
<td>9,610</td>
<td>8,616</td>
<td colspan="3">9,281</td>
<td>9,289</td>
<td>7,322</td>
<td>106,892</td>
</tr>
<tr class="odd">
<td>El Paso, TX</td>
<td>56,688</td>
<td>59,433</td>
<td>64,553</td>
<td>55,632</td>
<td>64,942</td>
<td>63,225</td>
<td>55,185</td>
<td>77,419</td>
<td>59,470</td>
<td colspan="3">63,671</td>
<td>51,107</td>
<td>49,081</td>
<td>720,406</td>
</tr>
<tr class="even">
<td>Fabens, TX</td>
<td>24</td>
<td>26</td>
<td>37</td>
<td>24</td>
<td>8</td>
<td>10</td>
<td>8</td>
<td>12</td>
<td>23</td>
<td colspan="3">20</td>
<td>9</td>
<td>13</td>
<td>214</td>
</tr>
<tr class="odd">
<td>Hidalgo, TX</td>
<td>28,647</td>
<td>30,544</td>
<td>36,420</td>
<td>30,726</td>
<td>32,856</td>
<td>31,603</td>
<td>30,371</td>
<td>33,627</td>
<td>29,833</td>
<td colspan="3">31,938</td>
<td>31,226</td>
<td>26,359</td>
<td>374,150</td>
</tr>
<tr class="even">
<td>Laredo, TX</td>
<td>114,829</td>
<td>121,675</td>
<td>133,952</td>
<td>112,419</td>
<td>131,385</td>
<td>131,162</td>
<td>119,027</td>
<td>134,678</td>
<td>126,296</td>
<td colspan="3">132,267</td>
<td>125,273</td>
<td>110,110</td>
<td>1,493,073</td>
</tr>
<tr class="odd">
<td>Presidio, TX</td>
<td>889</td>
<td>830</td>
<td>991</td>
<td>707</td>
<td>764</td>
<td>617</td>
<td>465</td>
<td>466</td>
<td>538</td>
<td colspan="3">693</td>
<td>960</td>
<td>814</td>
<td>8,734</td>
</tr>
<tr class="even">
<td>Progreso, TX</td>
<td>719</td>
<td>963</td>
<td>1,147</td>
<td>815</td>
<td>1,043</td>
<td>1,062</td>
<td>1,101</td>
<td>1,317</td>
<td>881</td>
<td colspan="3">751</td>
<td>1,168</td>
<td>1,034</td>
<td>12,001</td>
</tr>
<tr class="odd">
<td>Rio Grande City, TX</td>
<td>1,722</td>
<td>2,036</td>
<td>2,139</td>
<td>2,205</td>
<td>1,931</td>
<td>1,860</td>
<td>1,775</td>
<td>1,958</td>
<td>2,128</td>
<td colspan="3">2,189</td>
<td>2,048</td>
<td>2,074</td>
<td>24,065</td>
</tr>
<tr class="even">
<td>Roma, TX</td>
<td>1,121</td>
<td>1,116</td>
<td>1,347</td>
<td>1,025</td>
<td>1,316</td>
<td>1,081</td>
<td>1,095</td>
<td>1,167</td>
<td>1,001</td>
<td colspan="3">1,069</td>
<td>1,048</td>
<td>890</td>
<td>13,276</td>
</tr>
<tr class="odd">
<td><strong>U.S. - Mexico Border Total</strong></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td colspan="3"> </td>
<td> </td>
<td> </td>
<td><strong>4,525,579</strong></td>
</tr>
<tr class="even">
<td colspan="12">Key: U = Data are unavailable; Data for the port of
Calexico are typically reported as a combined total with Calexico
East.</td>
<td colspan="4"></td>
</tr>
<tr class="odd">
<td colspan="11">Source: U.S. DOT, BTS based on data from US Customs
Service, Mission Support Services, Office of Field Operations,
Operations Management Database.</td>
<td></td>
<td colspan="4"></td>
</tr>
</tbody>
</table>

# 

![](media/image2.png){width="6.553472222222222in"
height="6.624305555555556in"}

# Figure 1. The Laredo Border Crossing Region

![](media/image3.wmf)

####### Figure 2. Laredo and the Location of the World Trade Bridge

Data Collection Process

For this study, two data collection locations were used in each
direction. The "number 1" locations were located to the north or south
of where the truck cues were anticipated to form due to backups at the
primary Customs location or export booths. The "number 2" location was
immediately after the primary inspection booths. For consistency among
all border crossings visited for the overall project, the data
collection positions were distinguished by whether they were leaving the
United States (outbound) or entering the United States (inbound). For
the Laredo border crossing, outbound was designated as southbound
indicating that the trucks were traveling into Mexico. Inbound was
designated as northbound indicating that the trucks were traveling into
the United States.

Each data collector would use a handheld computer to record partial
license plate information of all commercial vehicles that passed their
location. The computer would also store the time that each license plate
was entered. The data from the two locations in each direction would be
combined, allowing the determination of the travel time for each vehicle
that was recorded at *both* locations.

For the data collection, the on-site team included four data collectors
and two supervisors. Thus, three team members were located in each
country. The hours during which data were collected were selected to
encompass the greatest number of daylight hours after the 8:00 AM World
Trade Bridge opening. They were selected from discussions with
knowledgeable officials. Table 2 shows the data collection hours for
each day during the site visit. Data collection extended about 10 hours
and included the periods when the supervisor collected data during break
periods and the meal period.

Figure 3 shows the Laredo, Texas portion of the World Trade Complex. The
data collection points are marked on the map. OB-1 is the location of
the data collector recording data on trucks moving into Mexico. OB-1A is
the location that the collector moved to when there was a backup from
the Mexican side. IB-2 is the data collection location for trucks coming
from Mexico and leaving the U.S. Primary Customs booths.

On the Mexican side of the border, trucks approach the World Trade
Bridge on a divided highway with two lanes in each direction. The
inbound trucks pass through the export booths of the Douanas (Customs).
A small percentage of trucks may be stopped for an additional export
inspection but the great majority proceeds through the bridge tollbooths
across the bridge to the U.S. side of the border. Trucks moving south
into Mexico pass the primary import booths, a small fraction are
diverted through an import inspection area then all trucks pass through
a secondary inspection booth before preceding on to the divided highway.
Figure 4 shows the location of the data collection points for both the
inbound and outbound directions. The IB-1 location was located at the
point where the trucks turned to head to the export booths. The OB-2
location was established to provide the best view of the front of the
trucks as they passed through the Mexican Customs import booths. Figures
5 through 9 show pertinent views of the U.S. and Mexican sides of the
World Trade Bridge.

For both directions in Mexico, there was a special lane for empty
vehicles. These included both bobtails and tractors pulling empty
trailers. The study team hypothesized that travel times could differ
between empty and full vehicles. Consequently the characters SC (Sin
Carga) were included to denote empty vehicles and to enable comparisons
of travel delay times between the loaded and unloaded trucks.

![](media/image4.wmf)

![](media/image5.wmf){width="9.859842519685039in"
height="7.482677165354331in"}

**Figure 5. Outbound Toll Booths at the World Trade Bridge**

![](media/image7.png)

**Figure 6. Primary Customs Viewed from the IB-2 Data Collection
Location**

![](media/image8.jpeg){width="5.352083333333334in"
height="3.5097222222222224in"}

**Figure 7. Inbound Access Booths (Export Booths) in Nuevo Laredo**

![](media/image9.jpeg){width="5.405555555555556in"
height="3.251388888888889in"}

**Figure 8. Access Road Approaching the World Trade Bridge in Nuevo
Laredo**

![](media/image10.jpeg){width="5.45in" height="3.2375in"}

**Figure 9. Outbound Import Booths in Nuevo Laredo**

## Table 2. Hours of Data Collection

  ---------------------- ------------------------ ------------------------
  **Date**               **Start**                **End**

  10/30/01               8:30 am                  7:00 pm

  10/31/01               8:30 am                  7:00 pm

  11/01/01               8:30 am                  7:00 pm
  ---------------------- ------------------------ ------------------------

## 

The arrangements that led to the data collection activities required a
considerable number of phone calls, e-mail correspondence, and a site
visit. A meeting was held at Laredo, Texas in June 2001 with
representatives of Mexican and U.S. Immigration, U.S. Customs, the City
of Laredo, the Mexican and American Consuls, and Battelle. In addition,
the Battelle representative toured the border area and potential data
collection sites with local officials. Table 3 contains a list of those
who attended the initial truck travel time delay orientation meeting.

Table 4 contains a list of the key individuals in Mexico who were
contacted and their telephone and e-mail information. A separate table
is included for contacts in Mexico and the United States. Table 5
includes information on contacts in the United States.

####### Table 3. June 2001 Meeting Agency Contacts

  ------------------------ ----------------------------------------------
  **Laredo Border Crossing 
  Coordination Meeting     
  Attendees**              

  **Contact**              **Agency**

  Daniel Hernandez Joseph  Mexican Consul, Laredo

  Thomas Hart Ambruster    American Consul, Nuevo Laredo

  Gabriel Cortes Sanchez   Mexican Immigration

  Jose Escamilla           Laredo Bridge System, City of Laredo

  Rafael Garcia            Laredo Bridge System, City of Laredo

  Eugenio Garza Jr.        U.S. Customs Port Director, Laredo

  Francisco Garcia         Chief Inspector, U.S. Customs, World Trade
                           Bridge

  Rene Leyendecker         U.S. Customs, South Texas Customs Management
                           Center
  ------------------------ ----------------------------------------------

## 

## Table 4. Contacts in Mexico

+------------------+-----------------------+-----------+-------------+
| **Border         |                       |           |             |
| Crossing         |                       |           |             |
| Contacts in      |                       |           |             |
| Mexico at the    |                       |           |             |
| Federal and      |                       |           |             |
| State Levels**   |                       |           |             |
+------------------+-----------------------+-----------+-------------+
| **Contact**      | **Agency**            | **Ph      | **E-mail**  |
|                  |                       | one/Fax** |             |
+------------------+-----------------------+-----------+-------------+
| > Claude Cortez  | Secretaría de         | > \(52\)  | > ccortezp  |
| > Papi           | Comunicaciones y      | > 55 19   | @sct.gob.mx |
|                  | Transportes (SCT)     | > 64 84   |             |
+------------------+-----------------------+-----------+-------------+
| > Victor         | > Central de          | > \(52\)  |             |
| > Rodriguez      | > Planeación Aduanera | > 52 28   |             |
| > Baggio         | >                     | > 33 82   |             |
|                  | > Servicios de        |           |             |
|                  | > Administración      |           |             |
|                  | > Tributaria          |           |             |
|                  | >                     |           |             |
|                  | > Secretaría de       |           |             |
|                  | > Hacienda y Crédito  |           |             |
|                  | > Público             |           |             |
+------------------+-----------------------+-----------+-------------+
| > Enrique Garza  | > Subgerencia de      | > \(52\)  |             |
| > González       | > Innovación y        | > 87 55   |             |
|                  | > Calidad             | > 07 12   |             |
|                  | >                     | > (       |             |
|                  | > Nuevo Laredo II     | Cellular) |             |
|                  | > Bridge              |           |             |
+------------------+-----------------------+-----------+-------------+
| > Lic. Beatriz   | > Subadministradora   |           |             |
| > Bautista       | > Nuevo Laredo III    |           |             |
| > Morgan         | >                     |           |             |
| >                | > Nuevo Laredo III    |           |             |
| > S              | > Bridge              |           |             |
| ubadministradora |                       |           |             |
| > Nuevo Laredo   |                       |           |             |
| > III            |                       |           |             |
+------------------+-----------------------+-----------+-------------+

#######  

####### Table 5. Contacts in the United States

+--------------+-------------------------+------------+---------------+
| **Border     |                         |            |               |
| Crossing     |                         |            |               |
| Contacts in  |                         |            |               |
| the United   |                         |            |               |
| States**     |                         |            |               |
+--------------+-------------------------+------------+---------------+
| **Contact**  | **Agency**              | **P        | **E-mail**    |
|              |                         | hone/Fax** |               |
+--------------+-------------------------+------------+---------------+
| Ana Einohosa | U.S. Customs, Assistant | \(956\)    | Ana.hinojosa@ |
|              | Port Director, Laredo   | 718-4179   |               |
|              |                         |            | Cust          |
|              |                         |            | oms.treas.gov |
+--------------+-------------------------+------------+---------------+
| J.J.         | U.S. Customs            | \(956\)    |               |
| Castillo     |                         | 726-2397   |               |
+--------------+-------------------------+------------+---------------+
| Rene         | U.S. Customs            | \(956\)    | RENE.LEY      |
| Leyendecker  |                         | 718-4161   | ENDECKER@Cust |
|              |                         | ext. 4184  | oms.treas.gov |
+--------------+-------------------------+------------+---------------+
| Rafael       | Laredo Bridge System,   | \(956\)    | Rgarci        |
| Garcia       | City of Laredo          | 791-2200   | a0@ci.Laredo. |
|              |                         |            |               |
|              |                         |            | TX.US         |
+--------------+-------------------------+------------+---------------+
| Gabriella    | Laredo Bridge System,   | \(956\)    |               |
| Salinas      | City of Laredo          | 791-2200   |               |
+--------------+-------------------------+------------+---------------+
| Frank Garcia | U.S. Customs, Assistant | \(956\)    |               |
|              | Port Director, Laredo   | 794-9401   |               |
+--------------+-------------------------+------------+---------------+
| Alex Agular  | U.S. Customs Supervisor | \(956\)    |               |
|              |                         | 794-9423   |               |
+--------------+-------------------------+------------+---------------+

Data Collection Details

Historical data was evaluated for an assessment of the variability in
travel conditions at the Laredo border crossing. The goal of this
analysis process was to obtain statistically useful data with as few
data collection days as possible. In order to customize the data
collection activities to Laredo, the following steps were conducted:

-   Define significant "seasonal" variations,

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-   Define significantly different days of the week,

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-   Identify traffic streams that experience significantly different
    conditions, and

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```
-   Estimate the number of days needed for the data collection survey.

Both the Mexican and U.S. Customs official provided some data on past
traffic flows at the border. Unfortunately, to date, the data collected
has been inconsistent. There weresufficient data to permit some analysis
and conclusions upon which data collection decisions were based. Daily
truck data from the U.S. Customs and the City of Laredo were provided
for first ten months of 2001. Table 6 shows that there is no clear
seasonal fluctuation in traffic volumes. As shown in the table, there is
not much variation is the commercial traffic by month for the data
presented. However, December for which data were not available from U.S.
Customs, likely exhibits a lower volume due to the holiday season. Due
to project constraints, data collection needed to occur between late
October and early November 2001.

The greatest fluctuations occur during the week. Sunday has the lowest
volume of truck flows and represents about ten percent of the average
weekday volumes. Saturday volumes are next lowest and represent about
one third of the average weekday volumes. Consequently, Tuesday,
Wednesday and Thursday were selected as data collection days because
they represent typical weekday truck volumes. There were no 2001 data
available for selecting sampling hours for the data collection at the
border. Interviews with U.S. Customs and Laredo Bridge personnel and
traffic counts taken by the Texas Transportation Institute (TTI) on
August 15^th^ and 16^th^ 2000, indicated that traffic volumes during the
day are somewhat different for each direction. For the outbound
direction, traffic volumes build slowly after the 8:00 AM bridge opening
increase until about 2:00 PM and peak about 6:00 PM before gradually
declining until about 7:00 PM and then sharply declining afterwards. In
the inbound direction, volumes rise rapidly in the morning, remain high
until about 6:00 PM when numbers of trucks crossing into the U.S. falls
off sharply. The goal of this analysis process is to obtain
statistically useful data with as few data collection days as possible.
As indicated above, a decision was made to collect only three days of
data from Tuesday through Thursday and that this would provide an
adequate number of data samples to represent "typical" conditions. Due
to availability of daylight, data collection began early in the morning
and continued until lighting conditions rendered data collection
impossible.

**Table 6. 2001 Truck Traffic at the World Trade Bridge**

**Source: U.S. Customs**

  ----------------------- ---------------------- ------------------------
  2001 Truck Traffic at                          
  the World Trade Bridge:                        
  Laredo, Texas                                  

  **Month**               **Inbound Trucks**     **Outbound Trucks**

  January                 84,762                 90,190

  February                79,617                 88,224

  March                   92,601                 94,287

  April                   82,581                 79,228

  May                     93,987                 85,584

  June                    87,098                 94,435

  July                    89,808                 97,971

  August                  98,965                 103,404

  September               87,970                 89,710

  October                 101,514                103,928
  ----------------------- ---------------------- ------------------------

Because the study team anticipated that travel times could differ for
loaded and unloaded trucks, data for loaded and unloaded trucks was
examined for the month of October. Table 7 shows that, at least for
inbound traffic from Mexico into the United States, slightly less that
half of the trucks are carrying loads.

**Table 7. Movement of Loaded and Unloaded Trucks into the U.S.**

+-------------+-------------+-------------+-------------+-------------+
| # Inboun    |             |             |             |             |
| d Truck Tra |             |             |             |             |
| ffic at the |             |             |             |             |
|             |             |             |             |             |
| **World     |             |             |             |             |
| Trade       |             |             |             |             |
| Bridge**    |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| *           | **Loads**   | **Empties** | *           | **TOTAL**   |
| *Oct-2001** |             |             | *Tractors** |             |
+-------------+-------------+-------------+-------------+-------------+
| MON 1       | 1,539       | 1,080       | 1,084       | 3,703       |
+-------------+-------------+-------------+-------------+-------------+
| TUE 2       | 2,364       | 1,095       | 1,433       | 4,892       |
+-------------+-------------+-------------+-------------+-------------+
| WED 3       | 2,314       | 861         | 1,138       | 4,313       |
+-------------+-------------+-------------+-------------+-------------+
| THU 4       | 2,151       | 951         | 1,225       | 4,327       |
+-------------+-------------+-------------+-------------+-------------+
| FRI 5       | 1,897       | 1,137       | 1,416       | 4,450       |
+-------------+-------------+-------------+-------------+-------------+
| SAT 6       | 654         | 179         | 538         | 1,371       |
+-------------+-------------+-------------+-------------+-------------+
| SUN 7       | 129         | 100         | 94          | 323         |
+-------------+-------------+-------------+-------------+-------------+
| MON 8       | 1,899       | 909         | 1,188       | 3,996       |
+-------------+-------------+-------------+-------------+-------------+
| TUE 9       | 2,071       | 821         | 1,074       | 3,966       |
+-------------+-------------+-------------+-------------+-------------+
| WED 10      | 2,082       | 980         | 1,185       | 4,247       |
+-------------+-------------+-------------+-------------+-------------+
| THU 11      | 1,987       | 889         | 1,190       | 4,066       |
+-------------+-------------+-------------+-------------+-------------+
| FRI 12      | 1,973       | 942         | 1,297       | 4,212       |
+-------------+-------------+-------------+-------------+-------------+
| SAT 13      | 656         | 188         | 451         | 1,295       |
+-------------+-------------+-------------+-------------+-------------+
| SUN 14      | 163         | 68          | 109         | 340         |
+-------------+-------------+-------------+-------------+-------------+
| MON 15      | 1,641       | 836         | 1,488       | 3,965       |
+-------------+-------------+-------------+-------------+-------------+
| TUE 16      | 2,003       | 979         | 1,194       | 4,176       |
+-------------+-------------+-------------+-------------+-------------+
| WED 17      | 1,882       | 971         | 1,290       | 4,143       |
+-------------+-------------+-------------+-------------+-------------+
| THU 18      | 1,785       | 893         | 1,145       | 3,823       |
+-------------+-------------+-------------+-------------+-------------+
| FRI 19      | 1,902       | 946         | 1,044       | 3,892       |
+-------------+-------------+-------------+-------------+-------------+
| SAT 20      | 715         | 269         | 686         | 1,670       |
+-------------+-------------+-------------+-------------+-------------+
| SUN 21      | 176         | 54          | 89          | 319         |
+-------------+-------------+-------------+-------------+-------------+
| MON 22      | 1,857       | 1,157       | 1,230       | 4,244       |
+-------------+-------------+-------------+-------------+-------------+
| TUE 23      | 2,031       | 1,042       | 1,341       | 4,414       |
+-------------+-------------+-------------+-------------+-------------+
| WED 24      | 2,107       | 892         | 1,115       | 4,114       |
+-------------+-------------+-------------+-------------+-------------+
| THU 25      | 2,013       | 1,078       | 1,176       | 4,267       |
+-------------+-------------+-------------+-------------+-------------+
| FRI 26      | 1,717       | 656         | 822         | 3,195       |
+-------------+-------------+-------------+-------------+-------------+
| SAT 27      | 757         | 396         | 433         | 1,586       |
+-------------+-------------+-------------+-------------+-------------+
| SUN 28      | 135         | 68          | 84          | 287         |
+-------------+-------------+-------------+-------------+-------------+
| MON 29      | 1,681       | 1,198       | 1,172       | 4,051       |
+-------------+-------------+-------------+-------------+-------------+
| TUE 30      | 1,994       | 797         | 960         | 3,751       |
+-------------+-------------+-------------+-------------+-------------+
| WED 31      | 2,006       | 937         | 1,173       | 4,116       |
+-------------+-------------+-------------+-------------+-------------+
| **TOTAL**   | **48,281**  | **23,369**  | **29,864**  | **101,514** |
+-------------+-------------+-------------+-------------+-------------+

**Data Collection Procedures**

The data collection stations selected for the crossing were chosen
because of the particular actions that occur at each site. Segments
defined by the data collection stations were used to determine the
commercial vehicle travel times and freight delay. As illustrated in
Figures 2 through 9, the data collection sites were located at:

-   An advance station located upstream of the commercial vehicle queue
    -- IB-1 and OB-1.

-   The import station (primary inspection booths before detailed, or
    secondary, inspection) -- IB-2 and OB-2.

Data collection was conducted by recording commercial vehicle license
plates as vehicles crossed fixed points within the data collection
sites. Survey individuals or teams, were placed at each of the four data
collection sites to record commercial vehicle license plate data.

Collectors at these locations would record the last five characters of
the front, lower-right license plate of as many trucks as possible that
passed their location. When trucking firms register many vehicles at
once, they often get assigned sequential license plate numbers. Using
the last five characters helps to ensure that as different trucks
operated by the same firm travel across the bridge that they are
uniquely identified. License plate information was entered into handheld
computers with a special application designed for this project. Each
entry was time-stamped with the current date and time. Prior to each
day's collection, all handheld computers were synchronized to the same
time. Prior experience indicated that recording the entire license plate
was too time consuming and that entering only the last four characters
did not provide adequate distinction between different vehicles, so the
project team chose to record the last five characters.

Typically, the queue of trucks crossing the border in outbound direction
(towards Mexico) did not extend beyond OB-1 as shown in Figure 3.
However, when the queue would extend northward the data collector at the
OB-1 location would have to move to the OB-1A to a point that was beyond
the end of the queue. In this way, the collector could continue to
record trucks before they began their wait at the end of the line. When
this or any other event of interest occurred, the collectors would use
an "EVENT" feature of the PDA software to record it. A similar process
was followed for the data collector at the inbound location (IB-1).
Where the queue of trucks backed up from the export booths, the data
collector would move south along the divided access road and resume data
collection at a point about 1.5 kilometers (.9 miles) south of the
Mexican export booths. The access road is shown in Figure 8. As was the
case for the data collector on the U.S. side of the border, when any
event of interest occurred, the collector would use the "EVENT" feature
to record it.

The data collection team used cell phones and hand-held 2-way radios to
communicate. This was particularly important when the queues lengthened
such that a collector had to move farther upstream. The supervisors
could be kept informed without repeated trips to each data collection
location. This was also useful at the end of the day when the #1
collectors would inform the #2 collectors of the last truck they
recorded, so the #2 collectors would know when to stop.

**Data Collection Sample Size**

Sample sizes are typically not a concern with videotape or handheld data
entry devices, because the data collection includes a large number of
vehicles. However, minimum sample sizes should be verified with
variability values from field data. Early research found that sample
sizes from 25 to 100 license matches were necessary for a given roadway
segment and time period (Turner, et. al.). In most cases, there were
sufficient records to meet this requirement.

**Data Collection Equipment**

As outlined in the "Data Collection Procedures" section above,
Handspring Visor PDAs were used as the data entry device and proved
adequate to the task. Low-end models with 2 Mb of storage capacity were
selected as the application and data size were projected to be well
below this limit. The Handspring Visors use the Palm OS (operating
system) and have faster processing speeds (at least in side-by-side
comparison with this application) and larger screen sizes than
comparable models from Palm Computing.

A custom application was developed for the Palm OS which allowed the
data collectors to identify their locations (e.g., IB-1, OB-2), the
number of open booths (primarily used for the Customs inspection
booths), special events or other comments, and license plate
information. A screen shot of the application interface is shown in
Figure 10.

![](media/image11.png){width="3.125in" height="3.3125in"}

**Figure 10. Data Collection Device and Software Application**

The data were downloaded via a serial cable directly from the
application into a text file on the field laptop computer, which was a
Dell Latitude CPx H running with a 500 MHz Pentium III processor.

**Data Collection Summary**

Table 8 shows the number of commercial vehicle license plates recorded
for each of the stations on each of the data collection days. On October
30, 2001, data was lost at the IB-1 data collection point due to a PDA
malfunction. Table 9 shows the matches for each direction for the data
collection days. Table 10 shows the average daily traffic volume as
recorded by the U.S Customs (inbound direction) and the city of Laredo
(outbound direction). Hourly volumes are used in the calculation of
delay; those are shown with the delay calculations in Tables 11 through
16.

**Table 8. Number of Commercial Vehicle License Plates Collected**

  ------------ ------------ ------------ ------------ ------------------------
  **Data                                              
  Collection                                          
  Site:                                               
  Laredo, TX**                                        

               10/30/2001   10/31/2001   11/01/2001   **Data Collection
                                                      Period**

  IB-1         NA           1,354        1,570        **2,924**

  IB-2         1,078        1,197        1,617        **3,892**

  OB-1         1,091        1,374        1,352        **3,817**

  OB-2         1,442        1,825        1,746        **5,013**

  Grand Total                                         **15,646**
  ------------ ------------ ------------ ------------ ------------------------

Table 9. Number of Matched License Plates Utilized

  -------------- ------------------ ------------------ ------------------
  **Station**    **10/30/01**       **10/31/01**       **11/1/01**

  IB             NA                 532                820

  OB             512                620                519

  Total          512                1,152              1,339
  -------------- ------------------ ------------------ ------------------

**Table 10. Average Daily Traffic at the World Trade Bridge Crossing**

  -------------------- ---------------- ---------------- ----------------
  **Direction**        **10/30/01**     **10/311/01**    **11/1/01**

  Inbound              3,751            4,116            4,012

  Outbound             4,293            4,429            4,312

  Total                8,044            8,545            8,324
  -------------------- ---------------- ---------------- ----------------

##### **Data Quality Steps**

At the end of each day of data collection, the supervisor would collect
the PDAs and download the data into the field laptop computer where it
was stored on the hard drive. The data would be examined for any
anomalies and transferred across the Internet to a secondary location
for backup purposes. The IB-1 and IB-2 data would be merged together and
license plates from the two locations would be "matched" using a
spreadsheet developed in Microsoft Excel. As it is easy to mistake
certain characters, particularly letters that looked like numbers, the
license plate data was pre-processed. All 'I's were replaced with '1's;
all 'O's, 'D's, and 'Q's were replaced with '0's; all 'S's were replaced
with '5's; and all 'Z's were replaced with '2's. In addition, the data
collectors were instructed to always use '1's for 'I's and '0's for 'O's
(i.e., to use the digit, rather than the letter).

Occasionally, collectors would be unsure about a license plate and would
append "QQQ" to their entry. This would typically occur when several
trucks passed the collector in rapid succession or if one truck blocked
the license plate of another and he or she could only manage a quick
glimpse. This would allow the supervisor to search the downloaded data
for a potential match by using the travel times of other trucks that
were recorded in the same general time frame. During this process, the
supervisor could also identify the few records in which the data
collector forgot to press "ENTER" after recording a license plate before
recording the next one. These ten-character entries could be split into
two and the time for the first interpolated from the adjacent entries if
they were less than a minute or so apart.

Data post-processing also included a step to identify any anomalies in
the data, including outliers. Outliers, records that indicated travel
times significantly greater than typical for that time period, were most
often caused by recording the license plate of a vehicle only some of
the time as it made repeated trips across the border during a single
day. This is because the matching algorithm uses the most recent time at
the #1 position when matching to a record from a #2 location. For
example, if the vehicle was recorded as it headed from Mexico to the
U.S. early in the morning, later returned to Mexico, was missed as it
re-entered the U.S. later in the day, and then recorded on its
subsequent return to Mexico, the #1 time from its first trip would be
matched with it #1 time from the first trip (for a valid travel time) an
also matched to the #2 time from its second trip (an invalid travel
time). This invalid travel time would be easily identified by manual
inspection of the data, aided by highlighting those travel times about a
certain, variable threshold.

## Freight Delay Analysis

The measure for the freight transportation system at international
roadway border crossings is travel delay per truck trip through the
first inspection point in the import country. Delay is measured relative
to the travel time at low volume conditions, which will allow the
processing time of the inspection to be accommodated outside of the
measure. Estimating the average delay per truck for each hour where
congestion is present, and then applying the average hourly truck volume
produces an estimate of total delay.

The average delay per truck for each hour is the difference between the
travel time at low volume conditions and the travel time each hour.
Travel time is also affected by the number of open inspection booths and
this information was recorded on all days as it changed. To determine
the average travel time for each road segment, the matched license plate
data in the database is used. The number of matches are noted for
statistical analysis and the travel time is noted for each hour. The
travel time for each truck was assigned to the hour when they passed
through the primary Customs inspection location.

The data are presented in Tables 11 through 15. The columns illustrate
the key elements for estimating delay:

-   No Delay Travel Time -- The time through the system at low volume
    conditions. For this report, the value used was that of the lowest
    hourly travel time in that direction for each three-day data
    collection period.

-   Average Number of Open Booths -- The average number of primary
    Customs commercial vehicle inspection booths open and available for
    processing trucks. This figure is not used to compute delay but is
    useful to help understand the relationship between booths, traffic
    volume, and delay.

-   Number of Matched Vehicles -- The number of vehicle observation used
    to estimate the travel time for each hour.

-   Average Travel Time -- The amount of travel time from entry to exit
    for trucks entering the system each hour (use the time the vehicle
    passes the advance point as the determinant of the time period
    label).

-   Delay per Trip -- The difference between the average travel time and
    the "no delay" time.

-   Average Traffic Volume -- The average hourly truck volume for the
    period being analyzed.

-   Total Delay -- The product of the hourly truck volume and delay per
    trip.

Note, as mentioned above, that inbound data for October 30, 2001 are not
available due to a problem with the data collection devices that could
not be corrected.

## Table 11. Total Delay -- 10/31/2001 -- Inbound

  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------
  **Time                  **(a)\    **(b)\     **(c)\        **(d)\    **(e)\   **(f)\       **(g)\
  Period**                \"No      Average    Number of     Average   Delay    Average      Total
                          Delay\"   No. of     \"Matched\"   Travel    Per      Traffic      Delay\
                          Travel    Open       Vehicles**    Time**    Trip\    Volume\***   (f x
                          Time**    Booths**                           (d -                  e)**
                                                                       a)**                  

  7:00       --   8:00 AM 5.43                                         -5.43                 0.00

  8:00       --   9:00 AM 5.43                                         -5.43                 0.00

  9:00       --   10:00   5.43                                         -5.43                 0.00
                  AM                                                                         

  10:00      --   11:00   9.73                                         (3.73)                0.00
                  AM                                                                         

  8:00       --   9:00 AM 12.23     6.00       23            35.67     23.44    309          138.00

  9:00       --   10:00   12.23     6.00       71            44.68     32.45    329          426.00
                  AM                                                                         

  10:00      --   11:00   12.23     5.54       46            32.83     20.60    288          254.84
                  AM                                                                         

  11:00      --   12:00   12.23     6.00       46            38.35     26.12    309          276.00
                  PM                                                                         

  12:00      --   1:00 PM 12.23     6.00       66            29.38     17.15    329          396.00

  13:00      --   2:00 PM 12.23     6.00       69            14.65     2.42     391          4140

  14:00      --   3:00 PM 12.23     4.43       69            19.47     7.24     309          305.67

  15:00      --   4:00 PM 12.23     5.00       70            26.38     14.15    288          350.00

  16:00      --   5:00 PM 12.23     5.94       57            14.78     2.55     247          338.58

  17:00      --   6:00 PM 12.23     6.00       15            12.23     0.00     309          0.00

  18:00      --   7:00 PM 12.23     5.67       23            35.67     23.44    370          130.41
  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------

\* Average traffic volume estimated by applying TTI traffic count hourly
inbound truck traffic percentages from 8/15/00 and 8/16/00 to U.S.
Customs data for 10/31/01

Table 12. Total Delay -- 11/1/2001 -- Inbound

  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------
  **Time                  **(a)\    **(b)\     **(c)\        **(d)\    **(e)\   **(f)\       **(g)\
  Period**                \"No      Average    Number of     Average   Delay    Average      Total
                          Delay\"   No. of     \"Matched\"   Travel    Per      Traffic      Delay\
                          Travel    Open       Vehicles**    Time**    Trip\    Volume\***   (f x
                          Time**    Booths**                           (d -                  e)**
                                                                       a)**                  

  7:00       --   8:00 AM 5.43                                         -5.43                 0.00

  8:00       --   9:00 AM 5.43                                         -5.43                 0.00

  9:00       --   10:00   5.43                                         -5.43                 0.00
                  AM                                                                         

  10:00      --   11:00   9.73                                         (3.73)                0.00
                  AM                                                                         

  8:00       --   9:00 AM 12.23     6.00       91            22.50     10.27    301          546.00

  9:00       --   10:00   12.23     5.05       102           20.35     8.12     321          515.10
                  AM                                                                         

  10:00      --   11:00   12.23     5.00       90            37.68     25.45    281          450.00
                  AM                                                                         

  11:00      --   12:00   12.23     5.00       80            55.02     42.79    301          400.00
                  PM                                                                         

  12:00      --   1:00 PM 12.23     5.81       97            58.63     46.40    321          563.57

  13:00      --   2:00 PM 12.23     5.99       79            53.32     41.09    381          473.21

  14:00      --   3:00 PM 12.23     5.99       77            36.25     24.02    301          461.23

  15:00      --   4:00 PM 12.23     5.44       89            29.13     16.90    281          484.16

  16:00      --   5:00 PM 12.23     5.00       78            17.73     5.50     241          390.00

  17:00      --   6:00 PM 12.23     5.00       37            20.75     8.52     301          185.00

  18:00      --   7:00 PM 12.23     6.00       91            22.50     10.27    361          546.00
  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------

\* Average traffic volume estimated by applying TTI traffic count hourly
inbound truck traffic percentages from 8/15/00 and 8/16/00 to U.S.
Customs data for 11/1/01

Table 13. Total Delay -- 10/30/2001 -- Outbound

  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------
  **Time                  **(a)\    **(b)\     **(c)\        **(d)\    **(e)\   **(f)\       **(g)\
  Period**                \"No      Average    Number of     Average   Delay    Average      Total
                          Delay\"   No. of     \"Matched\"   Travel    Per      Traffic      Delay\
                          Travel    Open       Vehicles**    Time**    Trip\    Volume\***   (f x
                          Time**    Booths**                           (d -                  e)**
                                                                       a)**                  

  7:00       --   8:00 AM 5.43                                         -5.43                 0.00

  8:00       --   9:00 AM 5.43                                         -5.43                 0.00

  9:00       --   10:00   5.43                                         -5.43                 0.00
                  AM                                                                         

  10:00      --   11:00   9.73                                         (3.73)                0.00
                  AM                                                                         

  8:00       --   9:00 AM 2.22      2.90       16            3.07      21:16    64           46.40

  9:00       --   10:00   2.22      3.65       30            4.97      20:16    129          109.50
                  AM                                                                         

  10:00      --   11:00   2.22      4.00       43            5.60      19:16    193          172.00
                  AM                                                                         

  11:00      --   12:00   2.22      4.00       56            7.60      18:16    236          224.00
                  PM                                                                         

  12:00      --   1:00 PM 2.22      3.04       39            8.35      17:16    236          118.56

  13:00      --   2:00 PM 2.22      3.00       46            17.37     16:16    301          138.00

  14:00      --   3:00 PM 2.22      3.33       41            25.63     15:16    343          136.53

  15:00      --   4:00 PM 2.22      5.91       102           33.03     14:16    386          602.82

  16:00      --   5:00 PM 2.22      7.00       89            20.48     13:16    386          623.00

  17:00      --   6:00 PM 2.22      7.00       50            19.45     12:16    408          350.00

  18:00      --   7:00 PM 2.22      2.90       16            3.07      11:16    472          46.40
  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ --------

> \*Average traffic volume estimated by applying TTI traffic count
> hourly outbound truck traffic percentages from 8/15/00 and 8/16/00 to
> City of Laredo data for 10/30/01

Table 14. Total Delay -- 10/31/2001 -- Outbound

  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ ----------
  **Time                  **(a)\    **(b)\     **(c)\        **(d)\    **(e)\   **(f)\       **(g)\
  Period**                \"No      Average    Number of     Average   Delay    Average      Total
                          Delay\"   No. of     \"Matched\"   Travel    Per      Traffic      Delay\
                          Travel    Open       Vehicles**    Time**    Trip\    Volume\***   (f x e)**
                          Time**    Booths**                           (d -                  
                                                                       a)**                  

  7:00       --   8:00 AM 5.43                                         -5.43                 0.00

  8:00       --   9:00 AM 5.43                                         -5.43                 0.00

  9:00       --   10:00   5.43                                         -5.43                 0.00
                  AM                                                                         

  10:00      --   11:00   9.73                                         (3.73)                0.00
                  AM                                                                         

  8:00       --   9:00 AM 2.22      3.58       37            2.22      0        66           0.00

  9:00       --   10:00   2.22      3.85       50            5.83      3.61     133          480.13
                  AM                                                                         

  10:00      --   11:00   2.22      4.00       79            17.10     14.88    199          2961.12
                  AM                                                                         

  11:00      --   12:00   2.22      4.00       60            29.42     27.2     244          6636.80
                  PM                                                                         

  12:00      --   1:00 PM 2.22      4.00       34            39.43     37.21    244          9079.24

  13:00      --   2:00 PM 2.22      3.73       62            45.33     43.11    310          13364.10

  14:00      --   3:00 PM 2.22      4.17       77            61.00     58.78    354          20808.10

  15:00      --   4:00 PM 2.22      7.28       106           44.42     42.2     399          16837.80

  16:00      --   5:00 PM 2.22      8.98       85            10.87     8.65     399          3451.35

  17:00      --   6:00 PM 2.22      8.00       30            13.88     11.66    421          4908.86

  18:00      --   7:00 PM 2.22      3.58       37            2.22      0        487          0.00
  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ ----------

\* Average traffic volume estimated by applying TTI traffic count hourly
outbound truck traffic percentages from 8/15/00 and 8/16/00 to City of
Laredo data for 10/31/01

Table 15. Total Delay -- 11/1/2001 -- Outbound

  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ ---------
  **Time                  **(a)\    **(b)\     **(c)\        **(d)\    **(e)\   **(f)\       **(g)\
  Period**                \"No      Average    Number of     Average   Delay    Average      Total
                          Delay\"   No. of     \"Matched\"   Travel    Per      Traffic      Delay\
                          Travel    Open       Vehicles**    Time**    Trip\    Volume\***   (f x e)**
                          Time**    Booths**                           (d -                  
                                                                       a)**                  

  7:00       --   8:00 AM 5.43                                         -5.43                 0.00

  8:00       --   9:00 AM 5.43                                         -5.43                 0.00

  9:00       --   10:00   5.43                                         -5.43                 0.00
                  AM                                                                         

  10:00      --   11:00   9.73                                         (3.73)                0.00
                  AM                                                                         

  8:00       --   9:00 AM 2.22      2.78       25            2.50      0.28     65           180.70

  9:00       --   10:00   2.22      2.96       39            4.30      2.08     129          381.84
                  AM                                                                         

  10:00      --   11:00   2.22      3.00       40            10.70     8.48     194          582.00
                  AM                                                                         

  11:00      --   12:00   2.22      4.01       46            20.52     18.3     237          950.37
                  PM                                                                         

  12:00      --   1:00 PM 2.22      4.30       62            8.72      6.5      237          1019.10

  13:00      --   2:00 PM 2.22      4.32       54            4.37      2.15     302          1304.64

  14:00      --   3:00 PM 2.22      4.26       55            14.42     12.2     345          1469.70

  15:00      --   4:00 PM 2.22      6.85       78            17.85     15.63    388          2657.80

  16:00      --   5:00 PM 2.22      7.85       87            5.05      2.83     388          3045.80

  17:00      --   6:00 PM 2.22      8.00       33            6.98      4.76     410          3280.00

  18:00      --   7:00 PM 2.22      2.78       25            2.50      0.28     474          1317.72
  ---------- ---- ------- --------- ---------- ------------- --------- -------- ------------ ---------

\* Average traffic volume estimated by applying TTI traffic count hourly
outbound truck traffic percentages from 8/15/00 and 8/16/00 to City of
Laredo data for 11/1/01

As mentioned above, data was collected all trucks and for trucks without
cargo because they were specifically treated differently at the Mexican
import and export booths. When delay times are compared for unloaded
trucks (including bobtails) and loaded trucks average delay time do
vary. Table 16 summarizes the weighted average travel times between
empty trucks and loaded flights.

Table 16. Delay Time for Empty and Loaded Trucks

  ------------------- ---------------------- ----------------------------
  Direction           Loaded or Empty        Weighted Travel Time

  Inbound             Empty Trucks           21.50 minutes

  Outbound            Empty Trucks           2.63 minutes

  Inbound             Loaded Trucks          32.39 minutes

  Outbound            Loaded Trucks          19.28 minutes
  ------------------- ---------------------- ----------------------------

## Statistics

Table 17 shows the baseline or "no delay" travel time, the average
travel time, and three other measures that indicate the reliability of
the travel time estimates. The baseline time (in minutes) is the time
needed to travel the study distance (between the starting point in the
exporting country and the initial inspection point in the importing
country) in free-flow traffic conditions. The average time is computed
from all vehicles measured during the data collection period over the
study distance. The 95^th^ percentile time is the time (in minutes)
within which 95 percent of all trucks can cross the border. The buffer
time is the additional time above the average crossing time (in minutes)
that it takes for 95 percent of all trucks to cross. The buffer index
expresses the buffer time in terms of the average time and is the
percentage of extra time that must be budgeted to cross the border
within the 95^th^ percentile time. For example, if the average time was
10 minutes and the buffer time was 5 minutes, the buffer index would be
50 percent.

Table 17. Crossing Times

+----------+-----------+----------+----------+----------+-----------+
|          | Baseline  | Average  | 95^th^   | Buffer   | Buffer    |
|          |           | Crossing | Pe       | Time     | Index     |
|          | Time      | Time     | rcentile |          |           |
|          |           |          | Time     |          |           |
+----------+-----------+----------+----------+----------+-----------+
| Outbound | 1.8       | 17.2     | 45.0     | 27.8     | 161.6     |
+----------+-----------+----------+----------+----------+-----------+
| Inbound  | 12.2      | 31.2     | 54.9     | 23.7     | 76.0      |
+----------+-----------+----------+----------+----------+-----------+

From the table, it is apparent that the average travel time is more
favorable for outbound traffic than for inbound traffic but that the
inbound traffic has higher reliability.

Figure 11 illustrates the average travel time experienced for different
truck volumes per lane per hour in each direction.

![](media/image12.wmf)

Figure 11. Average Travel Time for Different Hourly Volumes

Figures 12 and 13 show typical average hourly traffic volumes per booth
for the study period as well as the measured average hourly travel
times. In addition, the average number of open primary Customs booths in
each direction is shown.

![](media/image13.wmf)

Figure 12. Typical Inbound Traffic

## 

![](media/image14.wmf)

Figure 13. Typical Outbound Traffic

## Conclusions

Lessons learned during data collection activities in this project at
this site and at others along the Canadian and Mexican borders with the
U.S. have identified several issues that should be taken into
consideration to assist future data collection efforts. Some apply to
advance planning and the initial site visit and others apply more
specifically to the data collection activities themselves.

[Planning and Site Visits]{.underline}

-   Prior to conducting any data collection project, all jurisdictional
    and cooperating agencies should be made explicitly aware of the
    purpose and objectives of the study as well as all the details
    associated with the data collection project (e.g. dates, times,
    procedures to be followed during the data collection period, etc.).
    Failure to do so may result in confusion and possible delay of the
    study. This has been very time-consuming at some ports and should be
    adequately accounted for in the schedule. For some agencies,
    including U.S. Customs, it is important to contact both the federal
    and local levels. Some entities that should be contacted might not
    be readily apparent and can include construction companies working
    on public rights-of-way, state police and city officials. Some
    agencies provide verbal approval for the data collection and may
    even provide supporting documentation to their field staff, yet are
    reluctant to provide documentation for the data collectors to carry.
    Every effort should be made to obtain written authorization that can
    be carried by the data collectors, particularly from bridge
    authorities and immigration officials. In addition contacts with
    officials should be maintained between initial site visits and data
    collection if delays are encountered. At Laredo, although we met
    with representatives of the city of Laredo, who operate the World
    Trade Bridge, at the initial visit, by the time data collection was
    scheduled, a key individual had forgotten details of the earlier
    contacts. Consequently, the supervisor made additional contacts in
    order to receive the needed approvals for data collection activities
    on the bridge in an outbound (southbound) direction.

-   Prior to data collection activities, a general idea of traffic peak
    periods and conditions should be understood to optimize collection
    of appropriate traffic data and coverage of the appropriate times.
    This information should be obtained from discussions with
    knowledgeable officials and by examining historical traffic data.

-   Any additional data needs should be discussed explicitly with the
    appropriate officials. At some crossings, for example, average
    hourly truck volumes are not normally recorded and maintained, but
    can be if special arrangements are made in advance. Alternatively,
    it may be appropriate to use other means to measure truck volumes,
    such as roadway counters or having the data collectors indicate the
    vehicles that pass without their license plates being recorded
    (assuming continuous data collection during each day). These
    additional traffic volumes could be used to corroborate data
    provided by the local authorities or used if their planned data
    collection did not occur or there was some other problem in
    providing the data.

-   It is also important to be aware of special federal or local
    holidays on both sides of the border when scheduling data
    collections as these could affect traffic flows. Some minor holidays
    that occur on Mondays and Fridays, might not significantly affect
    traffic for a Tuesday through Thursday data collection period, but
    may increase the likelihood that key local officials will be on
    vacation and unavailable should any problems arise.

-   When scheduling the data collection times, consider the availability
    of sunlight or high-powered lighting. It becomes increasingly
    difficult to read license plates at night as trucks approach with
    their headlights on (also a problem during rain) and entering the
    data into the PDAs also becomes more difficult when it is dark. This
    was especially true in Laredo where during data collection, the sun
    set about 6:30PM and it became extremely difficult to collect data
    after that time.

-   Photographs of the border facilities and data collection locations
    should be taken during the site visits to assist in documenting the
    collection effort and to better inform the data collectors prior to
    their arrival on-site.

-   Processing, data quality, and analysis of all traffic data require
    the largest portion of the study time.

[Data Collection Activities]{.underline}

-   Prior to data collection activities, an explanation and
    understanding of the procedures to be followed and logistics should
    be made clear to all members of the study team (e.g., number and
    location of license plate characters to be recorded, all commercial
    vehicles should be recorded, when and how to contact the on-site
    supervisor, etc.).

-   Proper identification for all survey members and written
    documentation of authorization from all jurisdictional agencies
    should be carried at all times by all members of the study team,
    especially when conducting business in a foreign country.

-   The supervisor should assess all conditions upon arrival for data
    collection to note any changes from the site visit or prior
    collection activities. Sometimes unplanned construction or other
    events may alter the preferred data collector locations or the truck
    flow patterns.

-   While only one supervisor was originally planned for each data
    collection visit, it was determined that installing one supervisor
    on each side of the border was highly desired. One supervisor would
    be designated the overall site supervisor. This presented several
    benefits, the most important being added safety and security for the
    data collectors, particularly for a collector who needed to move to
    a remote location upstream from the border when the queue extended
    beyond their original location. Other benefits were increased
    awareness of current conditions and the origin of backups, the
    increased ability to relieve data collectors for breaks and lunch
    while maintaining continuous data collection, and assisting with
    data collection during exceptionally high-volume times or in
    difficult locations (such as remote spots along a highway when the
    vehicles were passing at free-flow speeds). Without the extra
    supervisor, a single supervisor would make repeated trips across the
    border to check on the collectors, relieve them, and provide them
    with food and drink if they were not conveniently located nearby.
    Border delays would often make this an extremely time-consuming
    process.

-   For Mexican data collection, it is recommended that Mexican
    nationals be used, both as supervisors and as data collectors. This
    helps to enhance coordination with national, state, and local
    officials and to minimize the likelihood of immigration or other
    problems with federal, state, or local agencies. A Mexican
    supervisor and data collectors were for the Laredo border data
    collection and resulted successful data collection on the Mexican
    side of the border.

-   As mentioned above, the supervisors should be used to maintain
    nearly constant data collection during breaks. This improves data
    quality by ensuring the supervisors repeatedly observe each
    collector and can identify and correct any problems they might be
    having. Further, this improves the number of trucks matched at both
    the #1 and #2 locations, improving the sample size for analysis.

-   Communication between the data collectors and their supervisors is
    crucial to an efficient and successful effort, particularly when one
    of the data collectors must move upstream past the end of a growing
    queue. Communication with the supervisor is also important when a
    data collector is having a problem with an official questioning
    their authority to do their work or when some other unexpected event
    occurs. For example, occasionally, there may be an anomaly with the
    data collection equipment and the collector can receive immediate
    instructions on how to proceed rather than having to wait until the
    supervisor next visits their location. Two-way radios (FRS-type with
    up to a two-mile range) and cell phones work adequately in most
    situations, but interference and range can limit their
    effectiveness. Cell phone service can be spotty near border areas.
    Additional longer-range communication options that do not require
    FCC approval should be considered for future collections. Obviously,
    when using cell phones, ensure that long-distance charges and
    roaming fees will not be significant costs.

-   It is important to ensure that the data collectors are safe and
    comfortable during their long periods of collection. If their data
    collection locations cannot provide adequate cover from severe rains
    or heat, additional vehicles should be considered. Comfortable sport
    chairs with attachable beach umbrellas served to protect the
    collectors well during light rain and moderate sun. Ensure that the
    collectors have an adequate supply of water and that facilities are
    conveniently accessible. This becomes more difficult for the remote
    locations upstream from the border crossing.

# REFERENCES

Turner, S.M., W.L. Eisele, R.J. Benz, and D.J. Holdener. *Travel Time
Data Collection Handbook.Report.* No. FHWA-PL-98-035. Federal Highway
Administration, Texas Transportation Institute, March 1998