"Table 2 Definition of the Dummy Variables Included in the Estimated Demand Equation
",,,,,
Dummy variables,Period,Comment,Expected sign,,
Z1–Z4,1994 – 1998,"They reflect the negative impact on traffic on the 4 A(2) motorway sections, derived from capacity and quality improvements on the alternative free road. ",–,,
Z5–Z7,1992,"They account for the positive impact on the 3 A(4) motorway sections, derived from the Seville World Exhibition in 1992.",+,,
Z8–Z11,1995 – 1998,They reflect the negative impact on traffic on 4 A(7) motorway sections as a consequence of the extension of an alternative tollway. ,–,,
"Z12, Z14, and Z16",1993 – 1998,"They reflect the negative impact on traffic on 3 A(7) motorway sections, derived from the opening of an alternative free motorway.",–,,
"Z13, Z15, and Z17–Z24",1990 – 1998,"They account for the positive impact on traffic on 10 A(7) motorway sections, due to the extension of this motorway.",+,,
Z25,1996 – 1998,It reflects improvements in the free alternative motorway network for the first of the A(19) motorway sections. ,–,,
"Z26, Z27, and Z28",1994 – 1998,They account for the positive impact on traffic on the 3 A(66) sections as a consequence of the improvement and extension of the motorway. ,+,,
"Notes: In Spain, the motorways (autopistas) are identified by the letter “A” followed by a number in parentheses. ",,,,,
These variables take the value 1 in the reported period; otherwise they are 0.,,,,,