Does anybody know how I might find out what the actual routing of 1 & 1D (and any applicable official libramientos) are through Tijuana? I am planning on being down there next month and would like to correctly clinch those highways.
I'm having a ton of difficulty finding any definitive evidence that Highway 1 actually connects to I-5, which is odd to me. The official Baja Map (http://www.sct.gob.mx/fileadmin/DireccionesGrales/DGP/Atlas/Mapa_2016/BAJA_CALIFORNIA.pdf) shows some routing of 1D through town, but it looks like maybe some cartographic liberties were taken.
I'm not sure if Mexico officially defines routes through cities. You may be able to figure out where federal maintenance ends using these:
http://www.sct.gob.mx/fileadmin/DireccionesGrales/DGST/Datos-Viales-2017/02_BAJA_CALIFORNIA.pdf
http://www.sct.gob.mx/fileadmin/DireccionesGrales/DGCC/PDF/bc_long_mar2017.pdf
The distances in the former don't seem to add up...it's only 1.6 km from km 22.00 to km 25.94. But it's roughly 80 km from km 22.00 to km 102.00, so maybe km 25.94 has the wrong coordinates. And km 22.00 is roughly 22 km from the border.
http://aga.sct.gob.mx/datosCarreterosAbiertos.do actually shows a route through the city. I'm having a shitload of trouble clicking on the segments to identify them, but I found the north end of 1 at Monumento a Cuauhtémoc. The roads to the northwest and northeast both have CODIGO=ND, while southwest is CODIGO=1. Old USGS topos show that the main road formerly turned northwest here on a now-gone street towards the border (visible on the 1968 aerial on http://www.historicaerials.com/viewer). So it could be mere laziness in updating the network over the decades.
But the libramiento also has CODIGO=1, from maybe-1D at a cloverleaf west of downtown south and east to a random point where it becomes 2 east of the right angle turn onto Diaz Ordaz.
That sounds like it starts to explain why Mexico signs routes junctioning themselves, because they've miscoded it (or even misdesignated it) internally.