Defining Managed Lane Option Users on the Katy Freeway

Option value refers to the willingness to pay for the option of having a service available for possible use at some time in the future, even if the option may never be used (Wallis, Wignall, and NZ Transport Agency 2012). From this definition, this research assumes that option users of the MLs are those travelers who occasionally or never use the MLs but use the GPLs on the freeway and have a transponder. These travelers could value the MLs for possible use at some time in the future because they can switch their lane to the MLs depending on traffic situations and travel needs.

When planning a trip, most travelers first choose their travel mode. They then choose a route to their destination. The choice between MLs and GPLs is a sub-decision of their entire trip route choices. Therefore, this research assumes all managed lane option users are those who use the Katy Freeway. In addition, in order to use the MLs on

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the freeway as an SOV, vehicles have to install a toll tag (transponder). This indicates that users who did not install the toll tag had no intention of using the MLs as an SOV, even occasionally. Therefore, since our data set includes all Katy Freeway travelers who installed a transponder, this research assumes all ML option users and their preferences are included in our data set. Clearly, other ML option users may exist based on other preferences, but we expect very few of these users.

From these assumptions, this research was able to define the option users of the MLs on the Katy Freeway in 2012 as the users who occasionally or never used the MLs in 2012 as included in our dataset and travelers who always used the MLs in 2012 were not option users. The users who occasionally used the MLs in 2012 could easily be considered as the option users of the MLs because they occasionally changed their lane choice from the GPLs to the MLs depending on their needs and were able to value the availability of the MLs as a backup. However, whether the users who never used MLs in 2012 are option users of the MLs requires additional consideration.

As mentioned, automobile travelers may value public transit service as a backup option for cases where they are unable to use their automobile due to breakdown or diverted usage (for example, loaning a car to family member or friend). Even travelers who never used public transit service are able to value the availability of public transit service because they cannot use their automobile and need other alternatives in such cases. Conversely, travelers on the freeway are always able to use the GPLs. Thus, the fact that a traveler never used MLs in 2012 would likely indicate that the traveler will continue to exclusively use GPLs in the future regardless of traffic situations and, hence,

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probably does not value MLs as an available option. Therefore, travelers who never used MLs in 2012 would probably not be option users of MLs. However, since it is still uncertain who the managed lane option users are and no previous studies have defined option users of MLs, this research considers two cases to estimate the option value of MLs in 2012: 1) Case 1 only includes the users who occasionally used the MLs in 2012 as option users and 2) Case 2 includes the users who occasionally or never used the MLs in 2012 as option users.

The data set identified in the previous section had 33,245,549 choices (trips) on the Katy Freeway in 2012. These trips include a total of 2,011,283 ML trips, and 31,234,266 GPL trips. From the dataset, this research identified a total of 1,604,804 travelers (vehicles) who traveled at least once with a toll tag (transponder) on the freeway in 2012. Table 18 classifies the 1,604,804 travelers by the percentage of trips that were on the MLs and the total number of trips in 2012 of each traveler. A total of 1,347,020 (83.9 percent) travelers never used the MLs in 2012 (see column a in Table 18), and a total of 214,859 (13.4 percent) travelers occasionally used the MLs (see column b in Table 18). A total of 42,925 (2.7 percent) travelers always used the MLs only in 2012 (see column c in Table 18), but they do not meet our definition of the option users. Thus, Case 1 considers the 214,859 travelers and Case 2 considers the 1,561,879 (=1,347,020+214,859) travelers for the estimation of the option value of the MLs. The 214,859 travelers in Case 1 made a total of 13,503,494 trips on the freeway and 86.8 percent (11,721,575 trips) of the trips were GPL trips in 2012 (see Table 19). The 1,561,879 travelers in Case 2 made a total of 33,016,185 trips on the freeway and

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94.6 percent (31,234,266 trips) of the trips were GPL trips in 2012 (see Table 19). In Case 1, the 13,503,494 trips are used to estimate utility functions of the ML and the GPL choices for the travelers, and, in Case 2, the 33,016,185 trips are used to estimate utility functions of the ML and the GPL choices for the travelers. Then, in each case, only GPL choices (trips) are used to estimate the option value of the MLs because, from ML choices, travelers value the MLs as the actual use value, not the option use value. These are 11,721,575 GPL trips and 31,234,266 GPL trips in Cases 1 and 2, respectively. A brief summary of the number of option users and their number of trips in each case is given in Table 19.

Table 18 Classification of Katy Freeway Travelers by Percentage of ML Trips

Number of Travelers (Vehicles) on the Katy Freeway in 2012

Percentage of Trips that were on the MLs in 2012

a) 0% b) 1-99% c) 100% Total Tota l Number of T rips o n the Ka ty F re ew ay in 2012 1-50 1,259,848 134,188 42,044 1,436,080 (89.5%) 51-100 50,635 36,420 503 87,558 (5.5%) 101-150 17,158 17,826 184 35,168 (2.2%) 151-200 8,080 10,589 91 18,760 (1.2%) 201-250 4,687 6,774 59 11,520 (0.7%) 251-300 2771 4269 23 7,063 (0.4%) 301-350 1812 2570 13 4,395 (0.3%) 351-400 1054 1291 4 2,349 (0.1%) 401+ 975 932 4 1,911 (0.1%) Total 1,347,020 (83.9%) 214,859 (13.4%) 42,925 (2.7%) 1,604,804 (100.0%) Note: a) indicates the users who never used the MLs in 2012, b) indicates the users who

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Table 19 Summary of Cases 1 and 2

Option Users

Total Number of Option Users

Total Number of Option Users’ Trips (MLs + GPLs Trips)

Total Number of

Option Users’ GPL Trips

Case 1 b) 214,859 13,503,494 11,721,575

Case 2 a) + b) 1,561,879 33,016,185 31,234,266

Note: a) indicates the users in column a and b) indicates the users in column b from Table 18