# Using Connected Vehicle Data to Evaluate National Trip Trends
## 6 Inter-State Trip Trends between US Census Places  
CV trip origins and destinations and the corresponding census blockgroup attributes identified in Table 1 were used to spatially aggregate trip counts and thus travel trends at the national level. A census place representing a named and locally recognized concentration of population as defined by the US Census Bureau [27] was chosen as the aggregation level for this analysis as an example. However, due to the granular census blockgroup level at which each CV trip origin and destination is recorded, alternative visualizations for any chosen census geographic entity, for example, state, county, census tract, zip code, or even core-based statistical areas, may be easily generated. CV trip origin and destination records were spatially joined to 8421 nationwide census places covering 118,067 census blockgroups (about half of the national tally) to formulate aggregate trip count numbers originating and ending in these census places. Following this, only those trips where the US state that the CV trip origin lies in did not match the destination's US state were selected to ensure only inter-state travel was visualized.  
To illustrate how CV trip patterns can be visualized, CV trips beginning and ending on 2 December 2022 Coordinated Universal Time (UTC) are plotted in Figure 3. This figure represents approximately 33 million trips that occurred that day. Figure 3a shows a spatial representation of trip counts among all census places, while Figure 3b depicts a similar visualization but only among census places with the keyword 'city' in their assigned legal/statistical area description (LSAD) name, thus being more indicative of inter-city travel at the national level.  
Trip counts shown are bidirectional in nature--for example, trips from Hammond, Indiana, ending in Chicago, Illinois, and those originating in Chicago, Illinois, ending in Hammond, Indiana, are represented by a single line segment. Solid blue dots on each figure indicate a census place location, while solid red lines indicate connecting links among the same, with trip counts directly proportional to the line segment's opacity. A significant concentration of trips is visible in census places along the East Coast as well as in major cities including Chicago, Omaha, Fargo, Memphis, New York, and Jersey City, to name a  
Figure 2: Share of Vehicle Trips by Length.  
few. The highest trip count nationwide was seen for travel between Kansas City, Missouri, and Kansas City, Kansas, at the Kansas-Missouri state border.  
These visualizations depict how CV trip data can be easily scaled to observe trip trends at any geographic level, aided in part by the geolocation accuracy associated with this data, which may not have been reportable using traditional survey-based methods of trip documentation. Such visualizations present insights into trip trends that may be useful for stakeholders in the decision-making process when allocating infrastructure improvement funds by providing quantitative real-world performance measures of corridor travel both inter- and intra-state.  
Figure 3: Inter-state Trip Counts between US Census Places (2 December 2022 UTC) (**a**) Trip counts between all US Census Places (**b**) Trip counts between US Census Places marked Cities.