7. 歴史の要約
Technique history Discussion
A: Location
Identification
A1:Transponder 1977 High cost, a few
operators
A2: AGS 1980 Less accuracy of data
A3: GPS 1997 Inappropriate in
downtown
B: Real-time
Information
Provision
Approach
-ing
info at
B1:Stops 1977 Convenient but
ineffective
B2: Facilities 1987 Effect unclear
B3: PCs 1998 Many operators
B4: Mobile
phones
1999 Many operators
Count down info at stops 1989 Much convenient