MARCO TEÓRICO
A. Permeabilidad de la vía aérea.
Travel Behavior
This section of the chapter will examine the relationship between travel behavior concerning walking/transit and the combined forces of personal values and the nature of the built environment. To visualize the combined impact of both pos- itive and negative influences on the use of walking and transit, a simple four-cell matrix will be used throughout this section. This format allows the user to examine variation separately (looking along either the rows or the columns) or together (looking at the relationship of the four cells to each other).
Creating the Four-Cell Matrix
The four-cell matrix shows the modal share associated with a combination of personal values (represented by the two
columns) and supportive neighborhood conditions (repre- sented by the rows). Table 8-9 shows the basic table, as well as the percentage of respondents that fell into each cell.
As Table 8-9 shows, when both the values and the envi- ronment are positive, the highest green mode share results (51%). When both the attitudes and the environment are negative, the lowest green mode share results (12%). For each “conflicted” group, when one factor is positive and the second factor is negative, the value looks something like the average value for the sample (24% green mode share).
The four-cell matrix shows how the two independent vari- ables interact. For example, if someone who holds a set of high urban/environmental values were to move into a CN, and if she were to act like others in the CN with similar val- ues, the result would be a high mode share for transit and walking. On the other hand, if someone with low levels of urban/environmental values were to move to a CN, and if she were to act like others in the CN with similar values, the re- sultant mode share would be similar to the average for the entire sample.
Relationship to the Theory of Planned Behavior
Seen in terms of the TPB, the urban/environmental values can be viewed as a combination of the attitude and the subjec- tive norm. Similarly, the extent to which the built environment either facilitates or impedes the adoption of the behavior can be viewed as relating to self-confidence. In our admitted sim- plification of the factors included in the TPB, the subjects with positive attitude/SN, whose decision is facilitated by the built environment, end up with 51% adoption of the behavior. The conflicted subjects with positive attitude/SN, but whose envi- ronment impedes the adoption of the behavior, end up with a near-average 24% adoption of the behavior.
On the other hand, the group whose attitude/SN is nega- tive, and whose environment tends to impede adoption of the behavior, winds up with only 12% adoption; the conflicted Neighborhood Mix Green Mode Share, All Trips (%) Transit Share, All Trips (%) Walk Share, All Trips (%) Monthly Utilitarian Walk Trips (No.) Mixed Housing Types 30 13 16 15 Single-Family Houses Only 15 8 8 7 Total Sample 24 13 11 12
Mixed housing/single housing paired values significantly different at p < .05; n
ranges from 450 to 415.
Table 8-8. Neighborhood housing mix and mode shares. Low Urban/ Environmental Values High Urban/ Environmental Values Living in CN 26% 51% Not in CN 12% 24%
Differences between row pairs and column pairs significant at p < .05; n= 333 to 65. Table 8-9. Location and values together—green mode share, all trips.
subject whose attitude/SN is negative, but whose environ- ment is encouraging of the behavior, ends up with a near- average adoption of the behavior (26%). Note that the ap- proach taken in this chapter is highly influenced by the logic put forward in the paper, Changing Individual Travel Be- haviour: From Policy to Perceived Behavioral Control, by S. G. Stradling (50).
Applying the Four-Cell Matrix to Walking and Transit
Table 8-10 shows the four-cell matrix applied to the green mode share for work and nonwork trips. In general, each of the cells of the matrix appears as expected, with both the con- flicted cells reflecting a value near the average work trip green mode share of 41%. As noted before, the work trip shows less variance associated with the two independent variables than does the nonwork trip.
The matrix for green mode share for the nonwork trip is also shown in Table 8-10. The lack of use of green modes for the nonwork trip for those outside the CNs and with low urban/environmental values is contrasted with the robust share for the opposite group. The values for the two con- flicted groups mirror the full sample nonwork mode share of 21%.
When the four-cell matrix is limited to transit mode share (Table 8-11), there are similar patterns as with the green mode share, except that many of the differences are no longer significant. In this table the differences that are not significant are indicated by pairs of percentages with the same superscripts. The CN residents take transit at a rate sev- eral times those in non-CNs. For the work trip, transit attracts a significant share from all four market segments, while for the nonwork trip transit mode split declines more sharply either for those in non-CNs or with low urban/ environmental values. Most work trip transit share differ- Green Mode Share, Work Trips
Green Mode Share, Nonwork Trips Low Urban/ Environmental Values (%) High Urban/ Environmental Values (%) Low Urban/ Environmental Values (%) High Urban/ Environmental Values (%) Living in CN 41 63 22 49 Not in CN 27 43 9 19
Difference between row and column pairs significant at p < .05; n= 333 to 58.
Table 8-10. Location and values together, by trip purpose.
Transit Share, All Trips Transit Share, Work Trips Transit Share, Nonwork Trips Low Urban/ Environ- mental Values (%) High Urban/ Environ- mental Values (%) Low Urban/ Environ- mental Values (%) High Urban/ Environ- mental Values (%) Low Urban/ Environ- mental Values (%) High Urban/ Environ- mental Values (%) Living in CN 16 x,y 27y 34a,c 47b,c 12 23 Not in CN 7x 12 24a 38b 2 6
Differences between row and column pairs (except subscripted pairs) significant at p < .05
n = 333 to 58. Differences that are not significant are indicated by pairs of percentages with the same superscripts.
Table 8-11. Location and values together—transit share by trip purpose.
ences in Table 8-11 are not significant. The exception is that, for those not living in a CN, there is a significant difference in transit mode share to work between the high values group and the low values group.
Turning to the walking patterns (Table 8-12), it becomes clear that, for each cell of our matrix, walk share does not vary much by trip purpose.
Looking at the data in terms of absolute number of walk trips per month, the most positive group takes about 26 walk trips per month, while the least positive group takes about five trips per month. The two conflicted groups each report about 12 trips per month, as shown in Table 8-13.