eu rome/History/provinces
e.g.
#93 - Rome
owner = ROM
controller = ROM
add_core = ROM
capital = "Rome"
culture = roman
religion = roman_pantheon
trade_goods = wine
population = 65
civilization_value = 90
barbarian_power = 0
split = 40.50.10
474.1.1 = { roads = yes forum = yes fort1 = yes temple = yes harbour = yes irrigation = yes } # Via Appia, constructed in 442. The Servian Wall. The Temple of Jupiter Capitolinus
482.1.1 = { aqueduct = yes } # Anio Vetus ( Aqua Appia - 442)
490.1.1 = { arena = yes } # The introduction of Gladiators
524.1.1 = { fort2 = yes }
554.1.1 = { population = 110 }
570.1.1 = { academy = yes } # Basilica Porcia
574.1.1 = { fort3 = yes }
# 608.1.1 - { temple = yes } # The Temple of Jupiter Stator
618.1.1 = { revolt_risk = 8 } # The First Servile War leads to food shortage
622.1.1 = { revolt_risk = 0 }
650.1.1 = { revolt_risk = 6 } # The Second Servile War
654.1.1 = { revolt_risk = 0 population = 200 }
666.1.1 = { revolt_risk = 10 } # Lucius Cornelius Sulla's first march on Rome
667.1.1 = { revolt_risk = 0 } # Lucius Cornelius Cinna is elected consul
# 669.1.1 = { irrigation = yes } # "De Agriculture", "De re rustica"
668.1.1 = { owner = RO2 controller = RO2 add_core = RO2 } # Gaius Marius returns from exile and takes control of Rome with Lucius Cornelius Cinna's help
672.11.1 = { owner = ROM controller = ROM remove_core = RO2 } # Sulla enters Rome
691.7.1 = { revolt_risk = 3 } # The Catiline Conspiracy - attempt to overthrow the Republic
691.10.20 = { revolt_risk = 8 } # Certain senators receive an anonymous letter bidding them to leave the city before the attack
691.11.1 = { revolt_risk = 5 } # The conspirators fail to seize Praeneste
691.12.5 = { revolt_risk = 3 } # Those conspirators still remaining in Rome are executed
692.12.9 = { revolt_risk = 0 } # Catiline is killed in Pistoria by Antonius
704.1.1 = { population = 170 }
705.3.10 = { owner = RO2 controller = RO2 add_core = RO2 } # Pompey flees and Caesar enters Rome
709.3.17 = { owner = ROM controller = ROM remove_core = RO2 } # The Battle of Munda
710.3.15 = { revolt_risk = 10 } # Caesar is assassinated
712.10.23 = { revolt_risk = 0 } # The Second Battle of Philippi
....
474.1.1 = { roads = yes
is what your looking at. That's the start date, and at that date that province has roads (since you can't go earlier effectively in all games, unless ofcourse you added a roads = no later, but don't forget that history is allmost entirely only red at the start of the game, so anything that is past your starting date is irrelevent)
If the province allready has
474.1.1 = { etc}
then add roads = yes with spaces either side to it, if the province has nothing at all then add
474.1.1 = { roads = yes }
Fairly straightforward