Editing Route number (section)

=== Czechia and Slovakia ===
[[File:Rudlice, silnice II-398 k Rudlicím (2016-09-28; 01).jpg|thumb|Sign of a second-class road II/398 in Czechia]]
[[File:Veselí nad Lužnicí, třída Čs. armády, směrovky.jpg|thumb|Highway D3 is different from the road I/3]]
[[File:Křižovatka Nová Hospoda 2.jpg|thumb|Route numbers on directional road signs]]
The numbering system of highways and road routes in Czechia and Slovakia is based on the original Czechoslovak system. Around 1946, first-class roads got their numbers 1–68. Numbers 1–60 belonged to Czech roads, 61–68 to Slovak roads. In 1950, an ordinance was issued (1199/1949 Ú.l.I) that divided roads into three classes, traditionally denoted by Roman numerals I (state roads), II (regional roads), III (district roads). However, the system of numbering roads of all classes was nationwide. Each route number was unique and one road could pass through several regions or districts under one number. Municipal roads were not included in the uniform numbering system. 

The number of digits of the route number corresponded to the road class. Class I roads had 1 or 2 digits, class II always 3 digits, class III 4 or 5, exceptionally 6 digits. On directional traffic signs, identification plates of bridge objects or in maps, the route number is given without a prefix. In texts, official decisions and announcements, the route number is usually preceded by a class designation with a slash (I/67, II/102, III/00425). At class I or II, the route branch can be supplemented with a letter suffix (capital letter), e.g. 8H can be a branch of the route 8, or 102A can be a branch of the route 102 – however, this index is not shown on regular maps or road signs. If the suffix letter (lowercase letter) is used for III-class road (III/10107a), the route marked in this way is a separate route and the letter suffix is an integral part of the route number.

Route numbers of I and II classes are sequential, meaningless. Some patterns can be traced to how the numbers were originally assigned by direction and area, but newly assigned or changed numbers may violate these patterns. Numbers of III-class routes are always derived from the number of some I-class or II-class route. The first three digits always indicate a reference route of a higher class, which means that I-class numbers are always supplemented by leading zeros to the three-digit number (III/0041 and III/00425a are both derived from I/4, and the number III/3259 is followed by III/32510). When I-class or II-class routes are renumbered or recategorized, III-class route numbers do not usually change because of this, i.e. they can refer to historical numbering, not to the current one.

Although plans and attempts to build highways in the area of Czechoslovakia had been made in the past, the first section of the modern highway network was opened on July 12, 1971. Highway numbers are mostly derived from I-class routes, which they replaced, e.g. road I/5 was replaced by highway D5. Highway numbers are usually indicated with the prefix D (D1, D47), in directional traffic signs they are indicated without a prefix and are distinguished only by the red color of the background. However, the highway number cannot be confused with the corresponding I-class road number, for example, the D8 highway goes in a different direction than the I/8 road. The prefix D is derived from the word "dálnice/dialnica", which is abbreviation of "long-distance road", the substantive "dálka" means "a (long) distance". 

Markings with the R prefix for "expressways" (rychlostní silnice, the word "rychlost" means "a velocity") were also used in the road network maps and strategic documents. R-roads did not have a separate numbering system, but they were sections of ordinary I-class roads, but in construction parameters and with a traffic regime similar to highways. 

After the dissolution of Czechoslovakia, the numbering systems of the two successor states (Czechia and Slovakia) became independent, but both continued to follow the Czechoslovak numbering system. 

The numbering system in Czechia remained in principle unchanged. However, especially during the partial changes in 1997, some numbers that originally belonged to Slovakia, especially from the 60s series, were used for I-class roads in Czechia, so they are duplicated compared to Slovakian numbers. The highways were renumbered so that the Slovak D1 highway no longer connects to the Czech D1 highway. Slovakia also started to use numbers for its roads that were originally used in Czechia. In Slovakia, a separate numbering system for expressways (R-roads) was created, with numbers R1 – R8. 

As of January 1, 2016, the highway network was reformed in the Czech Republic. The main change was that most sections of R-roads (expressways) were recategorized to highways and the R prefix has fallen into disuse for the remaining ones as well. 

In Slovakia, numbering of III-class routes underwent two reforms. First, in connection with the digitization of the road database, the way of writing third-class road numbers was changed so that in the data outputs all these numbers were complemented to six digits by inserting zeros, e.g. III/5196 to III/519006, however, the old numbering was also used at the same time. As of May 1, 2015, all Slovak III-class routes were renumbered to completely new four-digit numbers, while an interval is reserved for individual districts within which the numbers are assigned. E.g., III/063054 (referring to I/63) was renumbered to III/1460 (numbers starting with 145, 146, 147 belong to Komárno District).

In Czechia, there is also a national system of cycling route numbering. It is quite independent on road route numbering. Number of digits (1–4) corresponds to the route class, ie. one-digit numbers are for I-class long-distance routes, while 4-digits numbers for local IV-class routes. On the roads, cycling routes are marked with specific official orange-black directional road signs, and for local and off-road routes, stripe marks derived from [[Czech Hiking Markers System]] are used (with orange margin stripes instead of white ones). The guarantor of the numbering system is [[Czech Tourist Club]]. In addition, there are many local routes not included in this system.