DOI: 10.6084/m9.figshare.28644674.v1
title: <b>CHRONEX-US: City-level historical road network expansion dataset for the conterminous United States</b>

description: Geospatial datasets on the long-term evolution of road networks are scarce, hampering our quantitative understanding of how the contemporary road network has evolved over the course of the 20<sup>th</sup> century. However, such information is crucial to better understand the dynamics of road network growth and expansion, and to shed light on the consequences of (sub-) urbanization processes, such as increasing mobility, traffic congestion, land take and transportation inequality.CHRONEX-US (“<b>C</b>ity-level <b>H</b>istorical <b>R</b><b>O</b>ad <b>N</b>etwork <b>EX</b>pansion dataset for the conterminous <b>U</b>nited <b>S</b>tates”), is a geospatial vector dataset reporting estimates of the construction year for each road segment in densely and semi-densely built-up spaces within 693 core-based statistical areas (i.e., Metropolitan and Micropolitan statistical areas) in the conterminous US. CHRONEX-US is based on the USGS National Transportation Dataset (NTD), integrated with the historical settlement compilation for the US (HISDAC-US). CHRONEX-US reports model-based construction epoch estimates for urban and peri-urban local / residential road network segments, using three different model-based scenarios. The vector data inherit topological integrity from the NTD data allowing for routing and other connectivity-based analyses within temporal strata of urban road networks. CHRONEX-US vector geometries are attributed with the US Census Bureau’s MAF/TIGER Feature Class Code (MTFCC), enabling stratification of the data by road category. The CHRONEX-US data descriptor (preprint) is available here.CHRONEX-US is available as a ZIP file containing 693 GeoPackage (.GPKG) geospatial vector polyline data files, named ”chronex_us_.gpkg”, with being the 5-digit identifier (GEOID) of the CBSA as defined by the US Census Bureau. Each GPKG contains the NTD road network vector data (polyline) clipped to the GBUA 2015 extents, split at the GBUA boundaries of previous years. The spatial reference system is the local UTM projection for each CBSA, facilitating distance- and orientation-based analyses. The attributes are:MTFCC_CODE: The US Census Bureau’s MAF/TIGER Feature Class Code (MTFCC; see https://www2.census.gov/geo/pdfs/reference/mtfccs2019.pdf).yr_lower_M1: Earliest year of the estimated construction epoch according to model 1yr_upper_M1: Latest year of the estimated construction epoch according to model 1yr_lower_M2: Earliest year of the estimated construction epoch according to model 2yr_upper_M2: Latest year of the estimated construction epoch according to model 2yr_lower_M3: Earliest year of the estimated construction epoch according to model 3yr_upper_M3: Latest year of the estimated construction epoch according to model 3yr_&lt; lower,upper &gt;_&lt; min,max,mean,std,range &gt;: Statistics summarizing the estimates of the three models. The standard deviation (std) and the range can be used to measure agreement of the three models.NoData values of the year estimates indicate that the road network segment was not included in the specific model (i.e., not overlapping with any GBUA polygon after buffering. A lower year of “0” indicates an estimated road construction year &lt;1900.CHRONEX-US data descriptor (preprint): Uhl, J.H., Burghardt, K.,and Leyk, S. (2025). CHRONEX-US: City-level historical road network expansion dataset for the conterminous United States. arXiv preprint. arXiv:2506.16625 [physics.soc-ph], https://doi.org/10.48550/arXiv.2506.16625.Related work based on CHRONEX-US:Burghardt, K., Uhl, J. H., Lerman, K., & Leyk, S. (2022). Road network evolution in the urban and rural United States since 1900. <i>Computers, Environment and Urban Systems</i>, <i>95</i>, 101803.Burghardt, K., Uhl, J. H., Lerman, K., & Leyk, S. (2024). Analyzing urban scaling laws in the United States over 115 years. <i>Environment and Planning B: Urban Analytics and City Science</i>, <i>51</i>(9), 2249-2263.Burghardt, K., Uhl, J. H., Lerman, K., & Leyk, S. (2024). Universal Patterns in the Long-term Growth of Urban Infrastructure in US Cities from 1900 to 2015. <i>arXiv preprint arXiv:2412.13181</i>.Burghardt, Keith; Uhl, Johannes H. (2022). Historical road network statistics for core-based statistical areas in the U.S. (1900 - 2010). figshare. Dataset.CHRONEX-US is based on the National Transportation Dataset and the Historical, generalized built-up areas in U.S. core-based statistical areas 1900 - 2015 dataset (Uhl and Burghardt 2022). CHRONEX-US is part of the USRoadNetworkEvolution project.<br><br>