# Analysis of Road Sign-Related Factors Affecting Driving Safety with Respect to City Size
## 4 Results
### Analysis of Road Sign-Related Factors Affecting Driving Safety
#### 4.4.2 Analysis with Respect to City Size  
Because urban complexity, road congestion, population structure, and place name guide characteristics depend on city size characteristics, the classification of the spatial scopes of Seoul City, metropolitan cities, Gyeonggi region, and provinces is essential to compare their relative influences. Seoul is one of the largest cities in the world, with a high population density and a population of nearly 10 million. As a result, it is the city with the highest number of operating vehicles in South Korea. Seoul also features a complex urban structure and road network, with the irregular roads of old towns mixed with the grid-based road networks of new towns. Based on the ITS National Traffic Information Center, Seoul Traffic Information System, and 21 autonomous district control centers, the city government has established the nation's highest-level transportation system infrastructure in Seoul. It hosts various mobility projects, such as personal mobility and bike-sharing, and has undertaken the construction of future mobility infrastructure, such as electric and hydrogen vehicles. Metropolitan cities in South Korea typically exhibit populations exceeding 1 million and a level of transportation infrastructure that is higher than that of provincial settlements, but lower than that of Seoul. In contrast, the level of transportation infrastructure in provincial cities and counties is relatively low owing to the financial constraints faced by local governments; they also exhibit low population densities and demographics with high proportions of elderly residents. The Seoul Capital Area (SCA) of South Korea, comprising cities with high populations that have expanded around Seoul, exhibits the characteristics of a megacity-scale urban belt. According to resident population statistics from March 2022 (National Statistical Portal, KOSIS), the population of Seoul is 9,506,778, whereas the population of the Gyeonggi Province, which is a part of the SCA, is approximately 1.4 times larger than that of Seoul at 13,575,936. The Gyeonggi Province exhibits characteristics that are distinct from those of Seoul, metropolitan cities, and other cities and counties. To alleviate the high population density in Seoul, the first- and second-phase new town development policies have dispersed and spread the Seoul population, leading to a mix of Seoul citizens and existing residents in the Gyeonggi Province. Goyang City and Seongnam City, with populations of 1.08 million and 930,000, respectively, include representative first-phase new towns, such as Ilsan and Bundang, due to population dispersion policies. According to KOSIS statistics, high proportions (over 30%) of the population in several sections of the Gyeonggi Province--including Gwacheon City (47.6%), Hanam City (46.7%), Gwangmyeong City (43.5%), Guri City (40.9%), Namyangju City (33.3%), and Goyang City (32.4%)--commute to work or school from the Gyeonggi Province to Seoul. Additionally, because Gyeonggi Province is adjacent to Seoul, its urban structure and road environment also combine characteristics of new towns with those of rural areas in the outskirts of the Gyeonggi Province. Considering the characteristics of each city, we compared and analyzed the road sign-related factors affecting driving safety. As can be seen in Table 7, the influence of road signs on driving safety was observed to decrease by 61.6% among drivers aged 60 years or more compared to those in their 40s and 50s (reference) in rural areas (other cities and counties). Compared to drivers with 4-10 years of driving experience (reference), the influence of road signs on the driving characteristics of drivers with 11-20 years of experience was 57.4% lower (significant at the 0.1% level) and that of drivers with 21 years or more driving experience was 42.9% lower (significant at the 5% level) in metropolitan cities.