Comments at Arlington County Board, December 13, 2025.
Welcome members of the County Board and County Manager. On November 20 the Transportation Commission approved the RiverHouse PDSP based on a Multimodal Transportation Assessment (MMTA) provided by Nelson Nygaard.
Video of the meeting is currently unavailable, but members of the Arlington Ridge Civic Association, who spoke during public comment, told me that the commission addressed none of the issues they raised about the MMTA.
This is unfortunate, since the transportation impacts of this massive infill development are huge. In its current state RiverHouse provides 1,820 parking spaces for 1,676 units or a parking ratio of about 1.1 cars per unit (p.3). Table 1 (p.15) of the MMTA indicates that upon full buildout, there will be 2,019 spaces for 4,466 units or a dramatically reduced parking ratio of about .45 cars per unit.
New residents moving to Arlington to get out of their cars are probably good with that, but what about existing RiverHouse residents? They will be forced out of their cars not only due to lack of parking but also a road diet that reduces travel lanes from 4 to 2 on S. Joyce Street across from Pentagon Row, Figure 17 (p.33, see also p.106).
Not to worry about them. Nelson Nygaard concludes that although level of service (LOS) at two intersections–Army Navy Drive at S. Hayes and S. Hayes at 15th Street–will be seriously degraded upon completion of the project in 2035, the effects can be mitigated with signal timing changes (pp.112-113).
This finding appears to conflict with the driveway trip counts shown in Tables 22 through 24 (pp. 100-102) of the MMTA. Table 22 shows existing p.m. vehicle trip counts at 437. Table 23 shows 2028 p.m. vehicle trip counts at 599. Table 24 shows 2035 p.m. vehicle trip counts at 798 for an increase of 83 percent. This is a huge jump considering that most of the traffic will dump onto S. Joyce Street, which will have been reduced from 4 lanes to 2.
The Transportation Commission might not have been so ready to accept the MMTA’s sanguine conclusion that infill development of RiverHouse “will have a minimal impact on the surrounding transportation and roadway network (p. 2)” had it gone a little deeper into the weeds on S. Joyce Street. County Board has an opportunity today to correct that oversight and dig a little deeper.