What are the roads in Westeros like? Do they have regular matinence and upkeep? If so who does the upkeep? Are the Gold Road, Roseroad, Kingsroad, etc the Westeros equivalent of highways? Because somewhere it’s said Ellyn Reyne built roads. So I’m curious, what were medieval roads like and what would you expect Westeros roads to be like?

(First off: there’s a big caveat here that GRRM hasn’t put every road on the map, so there may well be roads we can’t see that change our perception. But based on what we know…)

They’re not great. 

Network:

There’s some pretty obvious missing connections when it comes to the system of royal roads created by Jaehaerys:

• The River Road should absolutely extend to Maidenpool, and there should probably be a Trident Road connecting Riverun Fairmarket and Seagard. 
• The Kingsroad should connect to White Harbor and Barrowton, with feeder roads linking White Harbor to Ramsgate, Barrowton to Torrhen’s Square to Winterfell, Kingsroad to Last Hearth to Karhold, and maybe Winterfell to Deepwood Motte to a ferry to Bear Island?
• The High Road should continue past the Eyrie to Gulltown, with a spur connecting the Eyrie to Ironoaks, Old Anchor, and Longbow Hall.
• We’re missing a north/south connection from Riverrun down to the Gold Road via Stoney Sept (which also connects you to the Blackwater Rush), and then down to the Roseroad via Bitterbridge.
• The Ocean Road should extend west to Kayce and north up the coast to the Banefort.
• The Reach needs an orbital road connecting Old Oak, Red Lake, Goldengrove, Bitterbridge, Ashford, and Horn Hill, connecting back to the Roseroad south of Highgardern. 
• The Stormlands should have a direct route from Bronzegate to the Roseroad that doesn’t require going more than a hundred miles north out of your way through a congested King’s Landing. It also needs the Kingsroad to extend further south than Storm’s End, linking up with the Weeping Town and Stonehelm where it can connect to the Boneway. 
• Dorne could use an eastern road continuing the Boneway from Wyl to Yronwood and Yronwood to Godgrace, and a western road linking Skyreach to Sandstone to Hellholt to Vaith. 

Bridges:   

There are not enough bridges in Westeros, and a lot of the bridges that do exist are wooden structures that don’t fare well under heavy flooding. So I would definitely add the following:

• Bridge over the Trident at the Ruby Ford, so that the main north/south highway in the whole kingdom doesn’t have to rely on a ford and some ferry boats. 
• Bridge over the Rush at King’s Landing, so that southbound traffic from the capitol to the Reach and the Stormlands doesn’t have to rely on ferries.
• Bridge over the Mander at Cider Hall or Longtable, over the Blueburn at Grassy Vale, and over the Cockleswent at Ashford, and over the unnamed Silverhall River at Goldengrove. In general, the Reach is bizarrely under-bridged and seriously impedes land traffic in favor of river-traffic. 
• Bridge over the Red Fork south of Riverrun, and a more secure bridge over the Blue Fork at Fairmarket. 

And yes, I know in some of these cases bridges might not exist due to defensive reasons (although that’s a double-edged sword; bridges work really well to stop Ironborn sailing their longboats up your rivers), but that’s why swing/draw bridges were invented.